1. Math haters are grave diggers
   1. #1: 2012 unlikely to repeat
   2. #2: GS Strength doesn’t compensate math weakness
   3. #3: One lakh Delhi aspirants
   4. #4: Maths = competitive edge + peace of mind
2. Mathematics: What to ignore?
   1. Doubtful syllabus topics in Mathematics
   2. Highest priority (finish them first)
   3. Medium priority
   4. Low Priority
3. CSAT Math doesn’t not fall from sky but NCERTs
   1. Gather the weapons
   2. Which Quant book?
   3. Don’t waste time learning Speed maths / Vedic maths
4. High priority topics
5. H1: Linear Equations
   1. NCERT: Linear Equations
   2. Quant book: Linear Equations
6. H2: Number system
   1. NCERT: Number system
   2. NCERT Powers & Exponents
7. H3: Percentages, Profit Loss, SI- CI
8. H4: Ratio Proportion Variation Partnership (RPVP)
9. H5: Speed Time Distance Work (STDW)
10. H6: Averages, Allegations
11. H7: Data Interpretation (DI)
    1. DI-1: odd- graphs
    2. DI-2: bar graphs, pie charts
    3. DI-3: Venn Diagrams
    4. Don’t assume A+B=total
    5. DI-4 Tabulation questions
12. H8: Geometry: Area volume perimeter (AVP)
13. Appendix: Download links
    1. A1: Last three years official CSAT papers
    2. A2: NCERT Mathematics Topicwise Sorted free download
    3. A3: Quant books: What to prepare, what to skip?

So far in the CSAT paper-2 study plan

1. Comprehension and Reasoning
2. Mathematics & Data Interpretation: high priority topics You’re here
3. Decision Making + Mathematics: Medium & low priority topics

Math haters are grave diggers

Many of you have this mindset / strategy:

1. I hate maths / I’m weak in maths. Therefore, I’ll pump extra hours in General studies to compensate for my poor command over mathematics.
2. Prelim marks not counted in final merit list, and maths is not going to be asked in mains. so why bother. Besides, in 2012 only 3 questions were asked!
3. xyz person on xyz forum said he managed to crack CSAT without preparing maths. Same Cinderella story will repeat in my case.
4. In last three years, average cutoff was ___. So, so if I tick __ Questions in GS paper I and __ questions in comprehension /reasoning, I can easily reach cutoffs, without bothering about maths.

To all such aspirants, I’ve four things to say:

#1: 2012 unlikely to repeat

% of questions	CSAT-2012 Paper II	CSAT 2013
comprehension	40 MCQs. (=50% of the paper)	reduced to 32 MCQs.
maths	only 3 MCQs = dream come true for math haters.	17 MCQs = = ~1/5th of paper.

Ok so why did the “Achhe din” end? Why didn’t UPSC ask just three Maths MCQs in 2013, like they did in 2012? You can unravel this mystery by looking at “Behind the curtains timeline” and joining the dots

20 May 2012	CSAT-2013 exam held. Only 3 maths and 40 comprehension.
30 August 2012	Prof. Nigvekar submits report & recommends following

• In CSAT Paper II: too many questions were asked from comprehension section, it needs to be reduced slightly in favor of other type of aptitude questions.(e.g. reasoning, maths)
• It will be better to reduce the English part in CSAT, and instead set bit tougher questions in the compulsory English paper at mains level.

26^th May 2013: CSAT 2013 exam. Comprehension reduced from 50% to 40%, consequently, maths questions increased from 3 to 17, to fillup the total 80 questions quota. Even in mains-2013, compulsory English paper was lengthier than previous exams, and hence tougher.

In other words, Maths is here to stay. 2012 scene unlikely to repeat. UPSC unlikely to ask only 3 maths MCQs in 2014.

#2: GS Strength doesn’t compensate math weakness

Prof.Nigvekar Committee observed:

CSAT Paper-I (General studies) is difficult compared to paper-II (Aptitude test). The candidates who are good in general studies, are at disadvantage, because they can’t get any edge with general studies. On the other side, candidates good in paper-II(Aptitude) gets advantage, & they can make though the exam even without much study of general studies. (Therefore)  Aspirants with engineering background formed the major chunk of aspirants who qualified the prelims in the first attempt.

In other words,

It takes far more effort to get 60 correct in GS, than it takes to get 60 correct in aptitude. Given the large influx of Engineer-UPSC aspirants post sub-prime crisis and mushrooming self-financed colleges, IF you (non-Engineers) think you can compensate your weakness in maths/aptitude by pumping more hours in General studies => then you’re making a grave mistake. You have to tame the bull (maths) by the horns (continuous practice).

#3: One lakh Delhi aspirants

In April 2014, UPSC wrote a letter to DoPT, requesting more officers to be deployed for exam duty because:

1. more than 10 lakh people expected to apply for CSAT-2014
2. Out of them more than 1 lakh people from Delhi alone. (This is UPSC’s estimation!).

10 lakh is not worrisome, because most of them are non-serious people applying just because papa said (JBPS). But 1 lakh from Delhi alone= that is a disturbing number.

• Because majority of them would be full-time dedicated aspirants migrated to Delhi for the sole purpose of UPSC preparation. Therefore, competition will be cutthroat than ever before.
• In recent years, even Hyderabad, Bangalore, Chennai, Indore, Lucknow and A’bad are also fast turning into Delhi like centres i.e. where many aspirants rent a room and full time dedicate to UPSC preparation with or without coaching.
• In this environment, you’ve to extract every mark you can, from every section you can. Hating maths is not a good idea. Remember: Sincere candidates don’t fail prelims by 100 marks, they fail by a margin of just few marks below the cutoff. And in most cases, they could have avoided failure by keeping alert on negative marking, and extracting a few easy questions from the subjects they disliked.

#4: Maths = competitive edge + peace of mind

• Today every sincere player knows he has to prepare NCERT, Laxmikanth, and Economic Survey. So command over those books = just minimum height n chest requirement in military recruitment. Not a competitive edge, doesn’t automatically ensure selection.
• Last year pretty much every regular reader of Mrunal.org ticked 12-15 correct in Economy. Again, no longer a competitive edge, it’s just a ‘minimum system requirement’ (MSR).
• People have been trying to get competitive edge over others by doing PH.D on Culture, science, environment. But given the tough nature of GS-MCQs, all that labour barely translates to additional 10-15 marks, that too after spending months in mugging up fifty dozen festivals, tribes, caves, algae/biofertilizers and critically endangered species.
• On the other side, maths can easily help raise your score by atleast 30** marks than the crowd, and ensure peace of mind until prelim result comes. Then, you can completely focus on mains preparation, rather than worrying about cutoffs in online forums.

**based on 2011 and 2013 trend, if UPSC asks 15-17 maths questions, then at least 12 of them will be solvable even with moderate preparation. 12 x 2.5 = 30 marks.

Mathematics / Basic Numeracy: How much upto ClassX?

Maths internal breakup in last 3 CSAT

Maths Topic	Subtopic	2011	2012	2013
Basic	HCF,LCM	1	0	1
	Ratio Proportion	1	1	4
	Linear EQ	1	0	1
	Subtotal: Basic	3	1	6
STDW	Speed Time Distance Work	2	1	4
Stat	averages	1	1	0
Data Interpretation (DI)	Pie chart	2	0	5
	Tabulation	3	0	0
	Speedgraphs Interpretation	3	0	1
	Bacterial growth	3	0	0
	Age pyramid	1	0	0
	Subtotal: DI	12	0	6
oddballs	Permutation combination (how many figures possible etc.)	3	0	0
	geometry	1	0	0
	AP, GP	1	0	1
	Subtotal: Odd balls	5	0	1
Maths Total	Basic+Stat+STD+DI	23	3	17
% out of 80 MCQs		28.75	3.75	21.25

UPSC’s official syllabus doesn’t specifically say “we’ll not ask this, this and this.” It only says:

• Basic numeracy (numbers and their relations, orders of magnitude, etc.) (Class X level)
• Data interpretation (charts, graphs, tables, data sufficiency etc. – Class X level)

This “etc.” word is dangerous. Because upto class X level NCERT textbooks include statistics, probability, trigonometry, parallelograms and even coordinate geometry. Should we prepare such topics or not?

CSAT system is just three years old. So far ~43 total maths questions asked in 2011, 12 and 13. This sample size too small to make projections that “x” topic will always be asked and “y” topic will never be asked.

2011: UPSC introduces CSAT system, public believed that UPSC will completely “revamp” its Aptitude Question bank in its secret computer database. But UPSC is still asking stuff they used to ask way back in the 90s. Observe:

CSAT paper II q. (maths / DI upto class X level)	similar asked in pre-CSAT era
2011 they gave a graph of A,B,C running and asked who won the race, who was very slow etc.	1996- with four athletes A,B,C,D
2011: water contamination, various phases	1999: fertilizer input vs yield
2011: comparing speed of two trains	1995: comparing temperature of two liquids
time speed distance Questions	Regularly asked between 1995-2012, with almost identical difficultly level.
linear equations, HCF-LCM questions	same as above

• This is just tip of an iceberg- even reasoning, syllogism, assumption-inference, Venn diagram, sitting arrangement- if you look at all the aptitude questions from 1995 to 2013- history is repeating itself from pre-CSAT era to CSAT era.
• Many questions are mirroring themselves only names, numbers and wording changed. if previously they gave time-distance & asked you to find speed; this time they give speed and time and ask you to find distance and so on

…..meaning

1. UPSC hasn’t completely revamped its question bank.
2. Just because xyz topic is not asked in last three CSAT = it doesn’t mean UPSC will never ask it in future exams. If something is taught upto class10, AND it has been asked in previous prelims (Even before Pre-CSAT era), then we should prepare.

Doubtful syllabus topics in Mathematics

Topic	Taught up to NCERT std.10?	Prepare for CSAT?	why?
Statistics (Cumulative frequency, median, mode etc.)	YES	YES	Yes, because in 1999 they asked Data interpretation (DI) about cumulative frequency and average for grouped data with class interval.
Arithmetic progression	YES	YES	asked in CSAT 2011 itself.
Geometric progression	NO	NO	GP starts from Class11. They did ask “water doubles every five minute” question in 2001, but it could be solved without formulas. At max, mugup the “ball rebounding” formula.
Irrational numbers	YES	No	it’s not asked from 1995 till 2013.
Coordinate Geometry	YES	YES	Asked in 1995 and 1999 prelims.
Non-AVP Geometry Theory	YES	YES	Non-AVP Geometry theory= interior angle, parallelogram sides, cyclic quadrilaterals etc. topics beyond simple area-volume-perimeter (AVP). YES should be prepared, because asked in 1995, 96, 97, 98, 99, 2000, 2001.
Trigonometry	YES	YES	height-n-distance problem has been asked in past. Ignore radian, maximum minimum values of sin/cos/tan- because that starts from class11-12 and never asked in pre-CSAT or CSAT era.
Clock Angles	indirectly	YES	Asked in 98, 2002, 2000 etc.
Divisibility	YES	YES	Asked in 2010.
Probability	YES	Yes	Routinely asked this topic up to mid-2000s.
Permutation &Combination (Pnc)	NO	YES	Yes. they routinely asked this topic upto mid-2000s, (may be Examiner considers this a “reasoning” topic and not maths) Even in CSAT 2011, they asked a question on fundamental counting- that topic is the mother of PnC, and starts only from class11 NCERT. in same CSAT 2011, they even asked image based PnC e.g. how many routes possible in 2×2 square diagram to reach from point A to B.
Polynomials,Quadratic Equations	YES	YES	Polynomial factorization related problems asked in 1995,96, 99, 2001 Pure mathematical questions related to Quadratic equation (e.g. nature of roots, find “k” etc. not asked so far)
Logarithms	NO	NO	Never asked between 1995-2013.
Venn Diagram	NO	YES	Venn Diagram starts from NCERT Class11. But they were regularly asked both in pre-CSAT and CSAT era. Perhaps examiner considers them part of “reasoning” and not mathematics or DI.

dang…these are way too many odd topics, can’t we just focus on time speed distance, linear equation, HCF-LCM? Hardly two months left before exam!!

Ans. No. You’ve to be prepared for all possible topics. UPSC examiner has no moral obligations to follow last year’s topic trend. 2011 he asks arithmetic progression, then ignores this topic for 2012 and 2013. If you aim to tick 10+ MCQs for a given subject, you’ve to be thoroughly prepared- whether its polity, geography, economy or aptitude.

Nonetheless, it may not be feasible to give justice to all the maths topic within ~2 months, so study-priority order should be following:

Highest priority (finish them first)

1. Linear Equation
2. Number System
3. %, profit loss, SI-CI
4. Ratio Proportion Variation
5. Speed Time Distance Work
6. Averages, Alligiations
7. Data Interpretation
8. Geometry: Area Volume Perimeter

Medium priority

Following topics not frequently asked, but takes barely 2 hours to master. because You just have to mugup 3-5 formulas and variety of questions is very less. Therefore cost: benefit good, You should make room in your schedule to prepare them.

9. Arithmetic Progression => only have to do one chapter in NCERT.
10. Coordinate Geometry => only have to do one chapter in NCERT.
11. Polynomials factorization => only have to do two chapters in NCERT.

Low Priority

Low priority doesn’t mean UPSC will *NOT* ask them. Low priority means, within your study time table, do them at last depending on how much free time left after allotting time for other high priority topics such as history, polity, science, economy, environment (for Paper I) and those reasoning-comprehension & other high priority topics under Maths (for Paper II).

Reason: following topics not frequently asked. They’re not difficult but have many variety of questions and formulas=> each of them take more than 4 hours to master. Therefore, put under low priority in terms of study time allotment.

12. Geometry theory: Triangles, Quadrilaterals, Circles (TQC)
13. Trigonometry: only height n distance
14. Permutation Combination Probability
15. Statistics

Anyways, let’s begin preparation:

CSAT Math doesn’t not fall from sky but NCERTs

Some questions directly came from NCERT, just numbers changed. Observe

CSAT paper II question	similar question in NCERT
2011: contractor penalty	Class 10, Ch 5, page 113, Q.15
2011: students who play neither cricket nor football.	Class11, ch1, page 23, example 26
2013: food in garrison, how many days will it last?	Class8, Ch13, page 212 example 7, 8 and 9.

Even the remaining questions, most of them are just slightly difficult than the concepts taught at NCERT level. Meaning, you don’t have to be an IIT/CAT ranker……If you can understand even upto NCERT level mathematics, you can tick good number of MCQs.

Gather the weapons

ESSENTIAL

One book on quantitative aptitude (hence forth referred as “Quant Book”) (For those really poor in maths)- NCERT Mathematics. Topicwise zip file given at bottom. one separate notebook / file, to maintain “diary of mistakes”- whenever you find any new formula, shortcut, weird MCQ or make mistake, note it down in this diary. Night before the exam, just read this diary. No need to “revise” aptitude books or practice sums on that night. I did the same for CAT, got 96%ile.

OPTIONAL

A folder and loose A4 sized papers-To maintain a diary of mistakes and shortcuts. This is better than a notebook because you can add new pages anywhere as per your requirement. A black slate, like those poor kids use in government primary schools-It saves lot of paper wasted in practicing math & reasoning sums. CSAT Topicwise solve papers (1995-2013) by Disha Publication. Contains all papers of GS and aptitude- topicwise separated for both pre-CSAT and CSAT era.

Which Quant book?

As such, CSAT maths is just slightly more difficult than NCERT exercises. BUT, since NCERTs alone don’t give all variety of questions and street-smart techniques to save time during exam. Therefore, you need a quant book. For example, consider this

(2007) A person has to fill three liquids – 403 lit. Petrol, 465 lt. diesel and 496 lt. motor oil in bottles of equal size without mixing any of above liquids. What is the least possible number of bottles required?

While NCERT teaches HCF in class10, but doesn’t dwell into this concept. Concept is: you’ve to find HCF (31), then divide each number with HCF, then you’ll get total number of bottles required = 44.

To learn all such variety of questions and concepts, you need a book on quantitative aptitude. NCERT are good to learn basic concepts, but NCERT alone are insufficient for CSAT.

Choice of Quantitative Aptitude book, depends on your career backup apart from Civil Service Exam.

IBPS, Bank, Staff Selection (SSC), AFCAT, LIC, NICL-AAO, ACIO, FCI & other PSU jobs.	Fast-track to Objective Arithmetic by Rajesh Verma
going back to private sector / business	CSAT Aptitude Manual by Tata Macgraw Hill (TMH), Arihant or Pearson or xyz publication- whichever you can find cheapest or second hand :-)
CDS, SCRA, CAT, XAT & other higher level exams.	Quantum CAT Sarvesh Kumar (OR Arun Sharma)

Avoid following books

RS Aggarwal’s book on Quantitative Aptitude, M.Tyra’s book on quicker Maths, and any other 90s era book that bookstorewalla recommends you, because:

1. They’re Useless for SSC, CDS and SCRA because they don’t give detailed coverage of Trigonometry, geometry theory (parallelograms, circle-tangent etc.) OR quadratic equations.
2. They’re Useless for CSAT and higher level exams. Because they don’t cover all variety of tricky MCQs asked in such exams.
3. Even banking & insurance exams – Rajesh Verma’s techniques are faster & easy to understand.

Don’t waste time learning Speed maths / Vedic maths

• For CSAT-Just memorize multiplication tables from 2 to 9. At max, mugup squares upto 19. It is sufficient.
• unlike Bank and CAT exam, the UPSC data interpretation questions don’t test your speed mathematics or long division skill,
• unlike CDS and SSC, UPSC questions on divisibility, number theory or HCF-LCM, don’t test your skill over prime number tables (13, 17, 19, 23, 29).

Therefore, don’t waste time in Vedic maths tricks for speed maths, addition, multiplication, subtraction, division, cube roots, square roots etc.

If you already know such tricks then good, but now is not the right time to learn them fresh.

High priority topics

High priority topics doesn’t mean UPSC will definitely ask majority of the questions from here. It only means while you plan your study schedule, you should finish them first:

H1: Linear Equations

Sample questions from previous prelims

• (1998) in a family, age of father is three times that of his daughter, and age of son is half of his mother. If wife is nine years younger than husband, and brother is 7 years older than sister, what is the age of mother? (Ans.60)
• (2009) A gave half of his coins to B and 4 more besides. B gave half of his coins to C and 4 more besides. C gave half of his coins to D and 4 more besides. Both B and D end up with same number of coins. How many coins did A have originally? (Ans.72 coins)
• (2011) a person has only Rs. 1 and Rs. 2 coins with her. If the total number of coins that she has is 50 and the amount of money with her is Rs. 75, then find the number of Rs. 1 and Rs. 2 coins with him? (Ans. 25 and 25)

What is Linear Equation?

Linear equation means unknown variable (x or y) doesn’t have anything above their ‘head’.

x2+2x+1	This is not linear equation because x has “2” above its head. Infact this is a quadratic equation. It is also part of “upto classs10” syllabus. But comes under “low priority” for CSAT.
2x+1	This is linear equation because x doesn’t have anything above its head. (Actually its x1 but for our understanding purpose, take it as just “x”). This is high priority topic for CSAT.

Linear equations are very important for aptitude exams, from two angles

1. direct MCQs about age, coins, salary, expenditure related problems
2. Indirect applications in time-speed-distance-work; profit-loss-SI-CI; Geometry problems etc.

L1: Age problems: silly mistakes

Q. 20 years ago, Bhootnath was 12 times the age of Abdul. At present, Bhootnath is twice as old as Abdul …blah blah blah

we’re presented with two conditions

Condition	Wrong	Right
20 years ago, Bhootnath was 12 times the age of Abdul	B-20=12A or B=12(A-20) (this is the most common mistake)	B-20=12(A-20)
Bhootnath is twice as old as Abdul	2B=A	B=2A

Many candidates make wrong equations as shown above, then get wrong answer. Examiner would have even listed wrong answer in option. So junta happily ticks such option, “my paper went so good”, then they fail & blame nepotism, corruption and DP Agrawal for everything.

How to avoid silly mistake?

In age problems, always prepare a table beginning with present age. Observe

At present, Bhootnath is twice as old as Abdul

present age
A and B
Eq1. B=2A

20 years ago, so make a column on left side:

Age 20 years ago:	present age
A-20 B-20	A and B
	Eq1. B=2A

Then make second equation: 20 years ago, Bhootnath was 12 times the age of Abdul

age 20 years ago (-20)	present age
A-20 B-20	A and B
Eq2. B-20=12(A-20)	Eq1. B=2A

Now plug the value of B from Eq1. into Eq2 and you’ll solve this effortlessly.

L2: keep minimum variables

Suppose the question is like this “The sum of present ages of Abdul and Bhootnath is 56. 5 years ago Abdul’s age was……….blah blah blah….find the present age of Bhootnath. ”

avoid this approach	use this approach
assume Abdul present age “A” Bhootnath present age “B”	assume Bhootnath’s present Age “B” assume Abdul’s present age =(56-B)
Here you assumed two variables “A” and “B”= lengthier calculations and increased chances of silly mistakes.	Here you’ve to worry about only one variable “B”. The moment you solve B, you get answer.

L3: Cannot be determined

Suppose you end up with two equations like this:

1. x+y=5
2. y+z=6

Here you’ve two equations but three variables (x, y and z). You can never find out the unique value of x, y, z in such situation. Hence answer = “Cannot be determined”. But sometimes, even two variable-two equation set can be impossible to solve. For example

No solution	infinite solution
x+ 2y=4 2x+ 4y= 12	2x+ 3y=94x+ 6y=18

• To learn more about ^this, refer to NCERT Maths Class 10, Chapter3, table given on the page #9.
• Examiner will test this by offering you both choice “Cannot be determined”; sometimes even data sufficiency (DS) question. Make sure you pick the right answer in right situation.

Anyways, let’s proceed with preparations:

@Those weak in maths	@Those good at maths
Following NCERT 7, 8 and 10, then refer your Quant book.	NCERT Class10. (Because it has some good CSAT level sums) Then refer your Quant book: Rajesh Verma or Sarvesh Kumar (not both).

NCERT: Linear Equations

Class	Ch.	What to focus for CSAT?
7	4	How to convert statements into simple equation. example 10 age problem on page 90 Exercise 4.4 question no. 2 and 3
7	12	12.5 Monomials, Binomials, Trinomials & Polynomials (page 233) 12.6 adding-subtracting simple equations. Solve the four questions given immediately. (page 235) 12.8 formula and rules. page 243 Formula for no. of diagonals in a figure. Page 246 Page 247 summary.
8	2	Point 2.3 the example given in it page 24 Page 25 Example 7 age problem page 26 Example 8 coin problem Page 26-27 examples 9 to 11 Exercise 2.2 do all the sums Page 30: Example 14 digit reversal Page 31: Example 15 about age problem Exercise 2.4 do all sums Page 35: example 19 age problem Page 35: Exercise 2.6 only do Problem 6 and 7.
10	3	Everyone should do this, irrespective of how strong / weak in maths. Page 46: In what situation, infinite solution / no solutions?  Table 3.4 most important for MCQs. Algebraic method to solve equations Page 50 understand the substitution method given in point 3.4.1 Page 52 Example 9: understand why the answer is “cannot be determined”. Page 53 Exercise 3.3 only solve Question No.3 Page 54 understand elimination method from example 11 Page 56 example 13: digit reversal problem Page 57 Do all the sums under Q.2 of exercise 3.4 Page 57: solve the apple sum under topic 3.4.5 but avoid the headache of that cross multiplication method. Stick to substitution & elimination methods. Page 60 ticket problem example 14 Page 63: do Q.(i) to (v) most important for CSAT. Page 65: example 19 avoid that stupid algebra method. Learn Boats and streams topic from my [Aptitude] article click me. Page 67

Quant book: Linear Equations

Rajesh Verma

Sarvesh Kumar

First solve chapter 27 then chapter 7.Chapter 27 linear equation Understand the consistency system given on first page of this chapter. then solve all the questions in illustration and exercises you may avoid following type of questions because no asked in UPSC Q.14 in Exercise1 Q1 on Exercise2 Chapter 7: Word problems based on numbers Focus on digit reversal problems and age related problems.

Ch13. Elements of Algebra in the initial part of this chapter he talks about polynomials, ignore it for the moment and directly move to page 525, “Linear Equation” He has explained all four methods to solve Linear equations. But stick to substitution and elimination method. Combined these two, you can handle pretty much every question. Ex.13: Do Question 10 to 18 Level 1: Do Question 23 to 31. Important: in Level1 exercises question No. 23 to 31: observe his explanations- how he solved them without assuming X or Y, or even framing equations. IF you master this technique, it’ll save a lot of precious minutes in the exam.

H2: Number system

Sample Questions from previous prelims

1. (2007) A person has to fill three liquids – 403 lit. Petrol, 465 lt. diesel and 496 lt. motor oil in bottles of equal size without mixing any of above liquids. What is the least possible number of bottles required? Ans. HCF will be 31. Then divide it with each number, you’ll get total number of bottles: 44.
2. (2009) while adding the first few continuous natural numbers, a candidate missed one of the number and wrote a wrong answer 177. Which number did he miss? Ans. Sum of the first “n” natural numbers is n(n+1)/2, but he missed “x”, so [n(n+1)/2] minus x = 177. Once you plug in the options, only x=13 will satisfy this equation.
3. (2011) three persons start walking together and their steps measure 40 cm, 42 cm and 45 cm respectively. What is the minimum distance each should walk so that each can cover the same distance in complete steps? Ans. whether its bells ringing together or bulbs lighting together or people walking together-you’ve Find LCM of those numbers. 25 m 20 cm
4. (2013) A gardener has 1000 plants. He wants to plant them in such a way that the number of rows and the number of columns remains the same. What is the minimum number of plants that he needs more for this purpose? Ans. Whenever you have to arrange soldiers or flowers or trees in Equal Row n equal column, then you have to make it square. Add 24 more trees so it becomes 1024=32×32.

These are not really difficult questions, most of them can be solved without mugging up any formulas. You just need a good grip over basic concepts.

POOR IN MATHS	GOOD IN MATHS
begin with NCERT (chapter wise list given below) Then use Quant books.	No need for NCERT. Directly use your Quant book. Refer to appendix of this article, for what to prepare and what to skip in the quant books.

NCERT: Number system

NCERT	Chapter	Topic to focus for CSAT
7	2.Fractions and Decimals	proper, improper, mixed fraction Ex.2.1’s example 6 Example 5 on page35 Example 6 on page39
	9. rational numbers	topic 9.7 comparison of numbers- page 179 example 6: direction sense test page 186 summary from page 191-92
8	1.Rational numbers	Table 1.2 the properties of rational numbers.Topic 1.4 how to find rational number between two rational numbers.
	16. Playing with numbers.	Divisibility rules for 2,3,5,9
9	1.Number system	basic concept of recurring decimals: example 8topic 1.6 laws of exponents for real numbers page 241.7 summary page 27
10	1.Real numbers	HCF, LCM how to find Page 10 Example 6, 8 and the remark given at bottom of it. Page 11: Question 7 important concept for circular race tracks. Page 19 note to reader. Ignore Euler and irrational numbers.

NCERT Powers & Exponents

NCERT	Chapter	Topic to focus for CSAT
7	13.Exponents & powers	comparing numbers with powers how even-odd powers change the sign of negative numbers 13.6 expressing large numbers in std.form
8	6. squares and square roots	table in 6.2 Numbers between square numbers- the lines given in italics. 6.4.2 Pythagorean triplets 6.7 estimating square root.
	7. Cube and Cube roots	geometry angle- example 7.2.2
	12.Powers	12.3 Laws of exponents, 12.4.1 Comparing very large and very small numbers.

Related articles under my [Aptitude] series:

1. LCM-HCF Simplified
2. Remainders: one number and two divisors

After this is done, you have to solve all questions from your quant book. Even solve the already solved sums given in the “illustrations”. Refer to bottom of this article “Appendix A3”, for what to prepare what to skip from Rajesh / Sarvesh.

H3: Percentages, Profit Loss, SI- CI

Sample Qs. from previous prelims

1. (1998) A man bought two clocks A and B for total Rs.650. He sold A at 20% profit and B at 25% loss. If he had kept selling price of both clocks the same, then what were the cost prices of each clock? Ans. It requires your understanding of linear equation, percentages and profit loss. A’s cost price 250, and B’s 400.
2. (2002) Trader fixed the price of an article in such way that by giving a rebate of 10%, he made profit of 15%. If the cost of the article is Rs.72, what is the selling price? Ans. 92 rupees.
3. (2005) Left pan of a faulty weigh weighs 100 gms more than the right pan. Shopkeeper keeps the weight measure in left pan while buying goods but keeps it in the right pan while selling goods. He only uses 1 kg weight. If he sells goods at the listed cost price, what is his profit? Ans. gist of the question is: he frauds 10% in buying and 10% in selling. So, on each trading sequence.

Hint: Assume 1 gm costs 1 rupee. Find per unit price while buying and selling.

buying fraud of 100 gm per 1000 gm = 1100 gm	selling fraud 100 gm per 1000gm = 900 gm
Unit cost price per gram= Rs.1000 paid/ per 1100 gm bought	unit SP =Rs. 1000 got/ per 900 gm sold
Effective cost price = 10/11	Effective selling price = 10/9

Profit % = (SP-CP/CP) x 100= 200/9%

This is one of those weird/unique question, so note it in your “diary of mistake”,

4.  (2010) two numbers X and Y are respectively 20% and 28% less than third number Z. By what % is the number Y less than number X. Ans 10%
5. (2010) Difference between simple interest from two banks on Rs.500 for two years is Rs.2.5, what is the difference between their rates? Ans. 0.25%

Percentages-NCERT

As such UPSC’s percentage related questions are complicated than the exercises given in NCERT, but still solve NCERT as warm-up exercise for multiplication and division.

• Class 7 Ch8
• Class 8 Ch8

To learn how to solve such MCQs, without mugging up formulas, refer to following articles:

1. Concepts of Marked Price and Successive Discounts (Profit-Loss) without (stupid) formulas
2. Compound Interest Rate, Population Growth without Formulas
3. Alligation: Advanced applications in Interest rates, Profit-loss, Average Wages (Wine-Water Concept)
4. Product Consistency: If Sugar price increases then consumption should be Decreased by What %, Time-Speed-Distance problems,

After this is done, you have to solve all questions from your quant book. Even solve the already solved sums given in the “illustrations”. Refer to bottom of this article, for what to prepare what to skip from Rajesh / Sarvesh.

H4: Ratio Proportion Variation Partnership (RPVP)

Sample Qs. from previous prelims

1. (1998) If 15 pumps of equal capacity can fill a tank in 7 days, then how many extra pumps will be required to fill the tank in 5 days? Ans.6 (you can solve this as “pipes n cisterns / speed-time-distance problem also. ultimately it’s a problem of inverse relation between speed vs time)
2. (2002) Amit Shah started a business with investment of Rs.30,000. Rahul Gandhi joined after some time and invested Rs.20,000. At the end of year, profit was divided in the ratio of 2:1. After how many months did Rahul join the business? Ans. 3 months
3. (2013) in a rare coin collection, there is one gold coin for every three non-gold coins. 10 more gold coins are added to the collection and the ratio of gold coins to non-gold coins would be 1: 2. Based on the information; the total number of corns in the collection now becomes what? Ans. 90
4. (2013) Out of 120 applications for a post, 70 are male and 80 have a driver’s license. What is the ratio between the minimum to maximum number of males having driver’s license? Ans. 3:7
5.  (2013) the tank-full petrol in Arun’s motor-cycle lasts for 10 days. If he starts using 25% more every day, how many days will the tank-full petrol last? Ans. 8 days.
6. (2013) In a garrison, there was food for 1000 soldiers for one month. After 10 days, 1000 more soldiers joined the garrison. How long would the soldiers be able to carry on with the remaining food? Ans. Inverse variation topic. Ans. 10 days.
7. (NCERT Class8) There are 100 students in a hostel. Food provision for them is for 20 days. How long will these provisions last, if 25 more students join the group? Ans. 16 days.
8. (NCERT Class8) The scale of a map is given as 1:30000000. Two cities are 4 cm apart on the map. Find the actual distance between them. Ans.1200

Understand the partnership concept from this article: (Aptitude)  Partnership and profit-sharing made Easy.

PS: Even those good at Maths MUST do the sums from Class8 Chapter 13.

Class	Ch.	What To Focus
7	8	Basics of Ratios. Although most of the chapter is focused on percentages. too rudimentary stuff, use it just for warm up exercise for multiplication  and division.
8	13	Basics of variation. page 207 example5 interesting Page 208 exercise 13.1 Question 5 to 10 Page 212 example 7, 8 and 9. Question 8. MOST IMPORTANT– how long the food will last. This type of questions asked in CSAT. Understand the concept well. Exercise 13.2 Q4 to 11. Notice Q5, its identical to the ‘food lasting’ problem.

Then solve your Quant book. Refer appendix for what to prepare, what to skip.

H5: Speed Time Distance Work (STDW)

This is fourth block, because these sums also test your understanding of Linear Equation (H1), LCM (H2), Percentages (H3) and ratios (H4). But Juntaa directly starts preparing STDW without learning first four blocks because last time UPSC asked many MCQs from STDW. Such quickfix-shortcut-moodswing based preparation usually lead to #EPICFAIL. You need good command over all those basic concepts from H1 to H4. Proceed in a systematic manner.

Sample questions from previous prelims

1. (2001) A worker reaches his factory 3 minutes late if his speed from his house to the factory is 5 km/hr. If he walks at a speed of 6km/hr, then he reaches the factory 7 minutes early. The distance of the factory from his house is ___? Ans 5 km
2. (2004) Two cars X and Y starts from two places A and B respectively which are 700km apart at 9 a.m. Both the cars run at an average speed of 60 km/hr. Car X stops at 10 a.m. and again starts at 11 a.m., while the other car Y continues to run without stopping. When do the cars cross each other? Ans 3:20PM
3. (2005) Aryan runs at a speed of 40meters/minute. Rahul follows him after an interval of 5 minutes and runs at a speed of 50 meters/minute. Rahul’s dog runs at a speed of 60 meters/minute and starts along with Rahul. The dog reaches Aryan and then comes back to Rahul, and continues to do so till Rahul reaches Aryan. What is the total distance covered by the dog? Ans 1200m
4. (2007) A and B can complete work together in 5 days. If A works at twice his speed and B at half of his speed, this work can be finished in 4 days. How many days would it take for A alone to complete his job? Ans 10 days
5. (2010) Three men start together to travel the same way around a circular track of 11km. Their speeds are 4, 5.5 and 8 kmph respectively. When will they meet at the starting point for the first time? Ans 22 hours
6. (2012) Mr. Kumar drives to work at an average speed of 48km/hr. The time taken to cover the first 60% of the distance is 10 minutes more than the time taken to cover the remaining distance. How far is his office? Ans. 40 km
7. (2013) A person can walk a certain distance and drive back in six hours. He can also walk both ways in 10 hours. How much time will he take to drive both ways? Ans. 2 hrs
8. (2013) A thief running at 8 km/hr is chased by a policeman whose speed is 10 km/hr. If the thief is 100 m ahead of the policeman, then the time required for the policeman to catch the thief will be what? Ans. 3 min
9. (2013) A train travels at a certain average speed for a distance of 63 km and then travels a distance of 72 km at an average speed of 6 km/hr more than its original speed. If it takes 3 hours to complete the total journey, what is the original speed of the train in km/hr? Ans.42 kmph

NCERT not much useful here, because it runs on the LCM method and doesn’t dwell on all varieties of questions.

STDW is made up of two topics

Speed time distance	cars, trains, platforms, boats etc.
Speed time work	“A can complete a work in….”, “pipe A can fill the tank in …” etc.

All of these can be solved through just one formula: STD (speed x time =distance). Go through following articles:

Time-speed-Distance	Time-speed-work
Trains, Platforms TSD (Time, Speed, Distance) made easy Boats and Streams made-easy using our STD-Table Method Average Speed made easy without Formulas STD table : Application in train man bridge, time and work problems Time n Distance: Early and late to office (shortcut using product consistency method) Product Consistency: Time-Speed-Distance problems	[Speed Time Work] Two Men can finish a work, A is 3x more efficient than B, B leaves before completion & variety of cases [Speed Time Work] Three men can finish a work in x days, A & B start work, C joins after x day, share in wages & other special cases Time n Work: 4 men and 6 women can complete a work in 8 Days then

Once you’ve understood this STD table concept, then apply it while solving the illustrations and exercises given in your quant book.

H6: Averages, Allegations

1. (1996) If the average of A, B and C is 14. Twice the sum of B and C is 30. What is the value of A? Ans. 27
2. (1997) the average monthly income of a person in a certain family of 5 is Rs.1000. What will be monthly average income of person in the same family if the income of one person increased by Rs. 12,000 per year? Ans. 1200
3. (2011) A student on her first 3 tests received an average score of N points. If she exceeds her previous average score by 20 points on her fourth test, then what is the average score for the first 4 tests? (Ans. N+5)

NCERTs don’t provide the street-smart techniques OR the requisite variety of questions asked in aptitude exams. They mainly deal from “Statistics” angle. (Statistics is asked but low-priority for CSAT).

So, instead of NCERTS, first go through following articles:

• [Aptitude] Averages: Entry / Removal of 1 element => Increase / Decrease in Average Shortcut method explained
• [Aptitude] Averages: More than two elements added / removed : shortcut technique explained
• [Aptitude] Alligations,Mixtures,Alloys: Water,Milk,Wine mixing: Weighted Average Made Easy for CSAT,CAT,CMAT,IBPS Aptitude
• [Aptitude Q] Mixture and Alligiation: Change Alcohol concentration from 15% to 32%
• [Aptitude] Alligation: Advanced applications in Interest rates, Profit-loss, Average Wages (Wine-Water Concept)

Then solve all the illustrations and examples from your Quant book.

if you really want to learn the basics, consult following NCERT chapter (although quite unnecessary because everyone knows this much basic.)

class	ch
7	3
8	5, 15 (These are useful for data interpretation though)
9	14
10	14

H7: Data Interpretation (DI)

GRAPHICAL	TEXTUAL
“Odd” speed graphs, bacterial growth graphs etc. bar graphs, pie charts, line graphs	Venn diagrams Tabulation

DI-1: odd- graphs

[Prelim 1995] The variations in temperatures form 0 degree C to 100 degree C with respect to time of two liquids P,Q are shown in the graph given below:

Which one of the following statements is correct?

1. During heating, liquid P remained hotter than liquid Q throughout
2. At no point of time during heating did the two liquids have the same temperature
3. P attained the temperature of 100 degree C faster than Q
4. Q attained the temperature of 100 degree C faster than P

ANSWER. (d)

[Prelim 1996] Following graph represents a race among four persons.

Consider following statements

1. A stood first in the race
2. C led all the way
3. D ran faster than others in the later part of the race.

Answer choices

1. 1 and 3 false, while 2 correct
2. 1 and 2 false, while 3 correct
3. 1 and 3 correct while 2 false
4. 1 is correct; 2 and 3 false.

Correct answer: (B)

hint: you should add numbers on both axis, then find what time each took to finish the race. you’ll see “D” won the race.

[Prelim 1999]The yield versus fertilizer input is shown in the graph.

Consider the following statements based on this graph:

1.Yield rate is zero at B and C

2.There is no yield with no fertilizer input

3.The yield is minimum at D

4.The yield is neither minimum nor maximum at C

Which of the above statements are correct?

1. 1,2 and 4
2. 3 and 4
3. 2 and 3
4. 1,3 and 4

ANSWER.(b)

[Prelim 2000]The following figure represents time vs learning curves of two students,Q and R for learning a Mathematics lesson:

Which one of the following can be drawn from the graph?

1. R started slowly in the beginning but got ahead of Q to complete learning the lesson
2. Q started slowly and finished learning the lesson earlier than R
3. R was always faster than Q in learning Mathematics
4. Q was always faster than R in learning Mathematics

ANSWER.(a)

Hint: add numbers on both axis, then you’ll see who is learning to what pace.
You’ll also find odd graphs in last three CSAT papers (attached at bottom of this article). I’m not copying them here because more images=slower loading webpage.

I call them odd graphs because usually unseen in other aptitude exams, even CAT. But these graphs are not falling from sky, topic is given in NCERT. First understand following concepts from NCERT Class8, Chapter 15 “Graphs”

• Page 234-35: Example1 two cricketers performance graph
• Page 235-36: Example2 car average speed graph
• Exercise 15.1: Q1 Patient’s temperature
• Page 237-38 Q3. growth of two plants A and B
• Page 238: Weather forecast vs actual temperature graph
• Page 239: understand the concept in Q7

In the real CSAT, usually they don’t give numbers on the axis. But if you want to solve them with NCERT technique, then you’ve to write numbers on your own understanding. Observe following image

Once you add numbers like this, it becomes very easy to compare P vs Q and eliminate options accordingly.

Where to get additional practice?

You’re unlikely to find such ‘odd graphs’ practice questions easily. They’re usually not asked in Bank and CAT. Although they’re sporadically asked in CDS, CAPF and SCRA exams (For all four major exams of UPSC, the Examiner seems to be utilizing the same DI Question bank from the secret server in the basement of UPSC Headquarter). But again cost:benefit not that great IF you start digging through all previous papers of CDS, CAPF and SCRA = too time consuming exercise. Anyways, you will find a few such question under

1. aptitude manuals
2. CST magazine’s mock tests.

You don’t have to specifically buy them only for the “ODD graphs”. Borrow whatever you can from library / friend circle.

DI-2: bar graphs, pie charts

• I’m not adding their samples questions here, because dozens of images =slow loading webpage, especially on mobile browser.
• But you’ll find the samples in the last 3 CSAT papers attached below the article.
• Difficulty wise- above SSC and little below BankPO

Data Interpretation in BankPO/ CAT	UPSC CSAT
Often require lengthy calculation and long divisions, even prime numbers (17,19, 23,37 etc.).	Usually calculations are easy – you’ve to do 10%, 20%, 25% of something and you’ll get the answer.
requires you to find exact mathematical answer. often the four options are very close (16.5,16.7,16.55,16.67) so you can’t eliminate wrong choices by logic or guestimation, you’ve to do exact calculation without any mistakes.	Usually give you 3-4 text statements and ask which one of them are correct as per the given chart. Meaning they don’t usually require you to find exact mathematical answer. Although you’ve to do maths /apply logic to eliminate the wrong statements.
To make difficult questions from pie chart, they usually make a combo of two pie charts OR 1 pie chart + 1 bar graph or 1 pie chart + 1 table.	Same

To get a basic overview of Pie charts, bar graphs etc you can consult NCERT class8 chapter 5. But as such it doesn’t contain any street smart tricks OR sums relevant to CSAT. Therefore, to gain command you’ve to get practice. Where to get practice DI sets?

1. SSC sets far easier than CSAT. so avoid
2. CAT sets will be an overkill. so avoid
3. Hence your best bet is bank PO exam papers. But even in them, avoid sets that require lengthy calculations and long divisions. Yes but where to get BankPO papers? Ans. hit the library and
   • go through monthly issues of Pratiyogita Darpan or banking service chronicle
   • CST (Civil service times) magazine gives demo CSAT papers with DI
   • Arihant/Kiran publication books papersets

Quant books usually don’t give many DI sets –whether it’s Rajesh, Sarvesh or Arun Sharma. It’s a clever marketing trick to sell another separate book for DI. But for CSAT DI, you don’t need any separate book. Also don’t waste time on internet gathering bank papers – they’re usually too scattered and bad PDF quality. Just hit the library and go through those magazines.

DI-3: Venn Diagrams

Sample questions from previous prelims:

1. [1998] There are 50 students admitted to a nursery class. Some students can speak only English and some can speak only Hindi. 10 students can speak both English and Hindi. If the number of students who can speak English is 21, then how many can speak Hindi, how many can speak only Hindi and how many can speak only English ? Ans. 39,29 and 11 respectively
2. [2000] In an examination, every candidate took Physics or Mathematics or both. 65.8% took Physics and 59.2% took Mathematics. The total number of candidates was 2000.How many candidates took both Physics and Mathematics? Ans. 500
3. [2001] In a survey,it was found that 80% of those surveyed owned a car while 60% of those surveyed owned a mobile phone. If 55% owned both a car and a mobile phone, what percent of those surveyed owned a car and a mobile phone or both? Ans. 85%
4. [2011-II] There are 100 students in a particular class. 60% students play cricket, 30% student play football and 10% students play both the games. What is the number of students who play neither cricket nor football? Ans.20

There are two sub types:

1. logical Venn diagrams (we saw in previous article)
2. mathematical Venn diagrams (that we’ll see here)

Don’t assume A+B=total

Q. In a society 10 people drink tea, 4 people drink both coffee and tea…..blah blah blah..find total people in the society.

Wrong Approach	Right Approach
Total people in society =+ only tea drinkers+ only coffee drinkers+ (those who drink both tea & coffee)	Total people in society =+ only tea drinkers+ Only coffee drinkers+ (Those who drink both tea & coffee) + Those who drink neither tea nor coffee (n)
This is juntaa’s most common mistake in Venn diagram. they forget about “n”	Read the question description carefully. If and when required take n=0.

As such Venn diagram is class11 topic but UPSC has repeatedly asked it both in pre-CSAT and CSAT era. Perhaps, examiner considers it “Reasoning” and not “maths”. Nonetheless, Venn diagram is a very easy “NO EXCUSE” topic. At max it should take ~3 hours to finish this topic at home.

Start preparation with Class11 NCERT Mathematics chapter1.

page	What to focus for CSAT?
16	Properties of intersections. you don’t have to mugup formulas, but understand the concept from those colored regions in those five image boxes.
17	Example 18. this is the “basic” of all 2 circle Venn diagrams.
21	Formula of n(AUBUC). As such you can solve 3 circle Venn diagrams with just logic of “this portion minus that portion”. but sometimes problems are trickier and you need this formula.
22-26	All the illustrations and all the exercises.
27	Q.13 to 16

After this, solve all the sums in your Quant book (+ whatever sums you get in Pratiyogita, CST etc.)

DI-4 Tabulation questions

Sample questions from previous prelims

[1996] The following table shows the percentage distribution of revenue expenditure of Government of India in 1989-90 and 1994-95 : Expenditure Head (percent to total)

Years	Defence	Interest payments	Subsidies	Grants to State/UT	other
1989-90	15.1	27.7	16.3	13.6	27.4
1994-95	13.6	38.7	8.0	16.7	23

Based on this table, it can be said that the Indian economy is in poor shape because the Central government continues to be under pressure to :

1. Reduce expenditure on defence
2. Spend more and more on interest payments
3. Reduce expenditure on subsidies
4. Spend more and more as grants-in-aid to State government/Union Territories

ANSWER.(b)

3. (2000) A club has 108 members. Two-thirds of them are men and the rest are women. All members  are married except for 9 women members. How many married women are there in there in the club? Ans.27
4. (2001) A city has a population of 3,00,000 out of which 1,80,000 are males. 50% of the population is literate. If 70% of the males are literate, the number of literate females is __.? Ans 24,000

You can solve Q3 and Q4 by directly framing linear equations. but table = less changes of error.

Sometimes, question descriptions of tabular vs Venn diagram sound very similar, but the main difference: the players in a tabular questions will not have “overlapping”. Observe

Tabular question	Venn diagram question
In a company ** male, out of them ** union members. Total female are **, blah blah blah…..then find __. in a company ** people work in HR, ** people work in R&D, ** people work in marketing blah blah blah….then find ___.	In a society 10 people drink tea, 4 people drink both coffee and tea…..blah blah blah..find total people in the society. in a society ** people own car, ** own bike….blah blah blah
Overlapping not possible. Man is man, woman is woman. You can make two columns: union vs non-union and further two sub columns man vs woman. same way, Person who works in HR cannot work in R&D at the same time. These are all separate columns. no overlapping circles.	Overlapping circles are possible, people who like tea, may also like coffee. Those who own car, may also own bike.

• This is not difficult, but juntaa doesn’t practice at home so in the exam they cannot decide which way to proceed- Should I make table OR Venn diagram? So, they simply start scribbling data either in table or in Venn diagram, until they get nowhere after 10-15 minutes of calculation.
• Then they try second approach, but make silly mistakes in addition / multiplication so finally after wasting 20 minutes they leave the sum.
• This is one of the main reasons why people cannot finish paper on time and fail in the CSAT.
• DONOT start scribbling numbers, UNLESS you know exactly how you’re going to reach the answer.
• Keep an eye on the wrist watch. DONOT spend so much time on a single question, even if it’s “Data interpretation”.

Anyways where to get practice?

NCERTs not much useful here. You’ll find some questions within Venn diagram chapter of your quant book. Beyond that

1. Previous papers of General Studies (Mains) paper II upto 2012. Because in those years, UPSC had statistics and DI section under Mains syllabus and they used to ask such tabulation questions.
2. Bank papers given in competitive magazines Pratiyogita, Banking chronicle etc. but keep in mind, UPSC’s tabulation MCQs don’t involve that lengthy calculations unlike IBPS/SBI.

H8: Geometry: Area volume perimeter (AVP)

Sample questions from previous prelims

1. [2005]A big rectangular plot of area 4320 meter square is divided into 3 square shaped smaller plots by fencing parallel to the smaller side of the plot. However some area of land was still left as a square could not be formed. So, 3 more square shaped plots were formed by fencing parallel to the longer side of the original plot such that no area of the plot was left surplus. What are the dimensions of the original plot? Ans. 120m x 36m
2. [2010]The diameters of two circular coins are in the ratio of 1:3. The smaller coin is, made to roll around the bigger coin till it returns to the position from where the, process of rolling started. How many times the smaller coin rolled around the bigger coin? Ans.3 times
3. [1998]A square pond has 2m sides and is 1m deep. If it is to be enlarged, the depth remaining the same, into a circular pond with the diagonal of the square as diameter as shown in the figure, then what would be the volume of the earth to be removed? Ans. (2pi-4)m³

How to proceed?

if you don’t have Sarvesh Kumar	if you’ve Sarvesh Kumar
First NCERTs then your quant book.	No need to consult NCERT. Because he has neatly summarized all theorms, formula and special questions given in NCERTs.

NCERT Class7 Chapter 11

206-208	all examples for area-perimeter related questions
220	example 15
221	example 16
223	do all exercises in 11.3
225-26	Example 20, 21, 22. Similar park-road question asked in 1997
226-28	all the sums and summary

Class9 Chapter 12: Areas related to triangles: HERON’s formula

199	Heron’s formula
201	example 2
202	all questions
203	Q.3 to 6; Example 4
205	ex.6
207	all questions and summary

Class9 Chapter 13: surface area volume. Proceed in following sequence:

237	first mug up all the formulas given in this summary
211-213	Cuboids area related sums
227-28	Cuboid volume related sums. 1995: UPSC asked question similar to example 11.
216-17	Cylinder area related sums
229-231	Cylinder volume related sums
220-21	Cone area related sums
232-33	Cone volume related sums
224-25	Sphere area related sums
235-37	Sphere volume related sums

Class10 Chapter 12

225	example cost of ploughing the field
226	entire exercise 12.1
227	formula for area of a sector
230	Q3, 8, 9
231	Q10 to 14
231-238	all illustration and sums important for CSAT. They keep asking such combo images and shaded areas.

Class10 Chapter 13

This chapter deals with volume of ‘combo’ figures. Semi-sphere above a cube & so on. Solve all the illustration and exercises given here.

— next article, we see how to approach the medium and low priority topics under mathematics for CSAT.

Appendix: Download links

A1: Last three years official CSAT papers

https://files.secureserver.net/0s4I32bAjTl3bm

except CSAT-2013, all contain official answerkey from UPSC

A2: NCERT Mathematics Topicwise Sorted free download

https://files.secureserver.net/0fmaNqqBDslHlc

A3: Quant books: What to prepare, what to skip?

Beyond NCERT, you’ll need to practice maximum sums from your quantitative aptitude book. However, not all chapters / topics given in such books, are important for CSAT. So, consult following PDF files on what topics to focus and which topics to ignore:

1. Fast track to Arithmetic Rajesh Verma What to prepare what to skip for CSAT
2. Quantam CAT Sarvesh Kumar What to prepare what to skip for CSAT

Visit Mrunal.org/aptitude for more articles on aptitude, maths, reasoning.