[Aptitude] Family Trees & Blood Relations: Logical Arrangement Made Easy

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  1. Introduction
  2. Dataset #1
  3. Dataset #2: UPSC CSP’2000
  4. Do eliminate wrong options
  5. Keep a Watch on the Watch
  6. Previous Articles on Aptitude

Introduction

  • Family relation / Family tree / Bloodline related aptitude questions are pretty common in CSAT, CMAT, IBPS and CAT.

Let’s try a very clichéd and easy question.

Dataset #1

There are 6 members in a family: A to F. There are two married couples, D is grandmother of A and mother of B, C is the wife of B and mother of F, F is the granddaughter of E.
Just like our Prime Minister, There is no ‘dum’ in this sum. It requires only three simple steps.

Step 1: Gender and Generation table

  • The data talks about three things: Gender (M/F), Generation(1/2/3) and Blood Relations (mom-son etc.)
  • If you try to arrange all three of them simultaneously, it’ll only lead to frustration and wastage of time. So first concentrate on two items only: Gender and Generation. The Relations will fall in line by themselves.

Given data: D is grandmother of A and mother …..
So D is the oldest Generation and she is definitely female.
But we don’t know whether A is male / female.
Anyways fill up the Gender – Generation table

GenerationMaleFemaleNot sure(M/F)
1 OldestD
2 Mid aged
3 YoungestA

Given data: D is grandmother of A and mother of B
Obviously “B” falls in the 2nd generation (mid-aged) but still we don’t know the gender of “B”.

GenerationMaleFemaleNot sure(M/F)
1 OldestD
2 Mid agedB
3 YoungestA

Given data: C is the wife of B and mother of F
This one statement, tells us three things

  • C is a female and mid-aged (2nd generation)
  • B is a male.
  • F is 3rd generation. But we don’t know the Gender of “F”

Update the table with this new information

GenerationMaleFemaleNot sure(M/F)
1 OldestD
2 Mid agedBC
3 YoungestA,F

Given data: F is the granddaughter of E
This tells us following

  • F is a female.
  • F is 3rd generation (although we knew it already.)
  • E is 1st generation and since “D” was female, this has to be male (Granddaddy).

Update the table

GenerationMaleFemaleNot sure(M/F)
1 OldestED
2 Mid agedBC
3 YoungestF*A

*intentional mistake.

Step 2: Checklist

  • In the arrangement questions: whether it is circular arrangement, linear arrangement or family tree: always runs the checklist after you’re done arranging the items.
  • If you had made any mistake in the arrangement, you’ll find it out at step2.
  • IF you proceed directly to solving questions, it may happen that you’ll get all answers incorrect. Because in aptitude tests, they design the 4 answers options (a/b/c/d) in such a way that even if you got incorrect arrangement, you’ll find answers matching to your arrangement!

So here is our final table

GenerationMaleFemaleNot sure(M/F)
1 OldestED
2 Mid agedBC
3 YoungestFA

And here is our checklist from the given question data

ChecklistPass/Fail
There are two married couplesPass
D is grandmother of A and mother of BPass
C is the wife of B and mother of FPass
F is the granddaughter of E.#EPICFAIL
  • Red light. STOP. Checklist item #4 is giving “Fail”
  • Haha see? I had made a stupid mistake in the table (intentionally).
  • F is granddaughter of “E” but I had mistakenly put “F” in the “Male” column.
  • In the actual exam, under the stress, many people make such silly-mistakes.
  • They calculate the sum correctly in their head but on the paper, their hand writes a different thing altogether.
  • Ofcourse in the actual exam, there is time-limit, so you can’t do cross verification/checklist in each and every aptitude question.
  • But in the ‘arrangement’ questions- each dataset comes with 4-5 questions. So, even one silly-mistake will cost you four times the negative marks. Therefore it’s always a good idea to run checklist on arrangement questions.
  • Our final “correct” table looks like this
GenerationMaleFemaleNot sure(M/F)
1 OldestED
2 Mid agedBC
3 YoungestFA

If you want to construct a family tree, it’ll look like following

IAS IPS CSAT IBPS Aptitude Notes

Greenlight. Proceed further. Time for some Questions.

Questions based on the Family-Data

Q1.Who among the following is one of the couples?

  • CD
  • DE
  • EB
  • Cannot be determined
  • None of these

well look at the table

GenerationMaleFemaleNot sure(M/F)
1 OldestED
2 Mid agedBC
3 YoungestFA

There are two couples : ED and BC
Final answer: (b) DE is one of the couple.

Q2. Which of the following is definitely false?

  • a) A is brother of F
  • b) A is sister of F
  • c) D has two grandsons
  • d) Cannot be determined

From the table

GenerationMaleFemaleNot sure(M/F)
1 OldestED
2 Mid agedBC
3 YoungestFA

We are not sure about A’s gender. A can be brother OR sister of F.
So option (a) and (b) are eliminated. We cannot definitely say which of them is false.
But checkout the third option (c), it says “D has two grandsons
Now this is definitely false because we know for sure that granddaughter “F” is a female. So Grandma “D” cannot have two grandsons in any case.
Final answer: (c)

Q3. How many female members are there in the family?

  • 2
  • 3
  • 4
  • Cannot be determined
  • None of these.

Since we don’t know the gender of “A”, we cannot determine the number of males and females in this family.
Answer:  Cannot be determined.

Anyways that was quite an easy dataset. Let’s try something a bit complicated.

Dataset #2: UPSC CSP’2000

There are 6 people in a family: A to F

  • Men and women are in equal number
  • A and E are sons of F
  • D is the mother of two: one boy and one girl
  • B is the son of A
  • There is one married couple in the family at present.

 

Step #1: Gender and Generation table

Given: Men and women are in equal number

Obviosuly, this means the family has 3 men and 3 women. How else do you distribute 6 into equal numbers otherwise!
Given: A and E are sons of F
It tells us three things

  • A and E are males
  • F is one generation higher than A,E. It means “F” is definitely not in the 3rd (youngest) Generation.
  • But no exact idea about gender or generation of “F”.
GenerationMaleFemaleNot sure(M/F)
1 Oldest
2 Mid aged
3 Youngest
0 (Not Sure)A,E (2/3)F(1/2)

^Notice this time I’ve also made an extra row “0(Not sure)” to accommodate A and E. The (2/3) suggests that A and E can be either 2nd or third generation.
Given: D is the mother of two: one boy and one girl
It tells us two things

  • D is female
  • D is not the youngest (3rd)generation, because she has kids. Thus She falls either in 1st or in 2nd generation.

Update the table

GenerationMaleFemaleNot sure(M/F)
1 Oldest
2 Mid aged
3 Youngest
0 (Not Sure)A,E (2/3)D(1/2)F(1/2)

Given: B is the son of A
Tells us many things

  • B is male. Because opening statement of the dataset said “equal number of men and women” and Since A,E and B are sons (males) therefore C,D and F are females. C is a female but we don’t know her generation: 1/2/3.
  • We already know that “A+E are sons of “F”. Therefore A cannot be in 1st generation. (warnaa uski Maa “F” kidhar jaayegi?)
  • It means A is definitely 2nd generation male. Because A cannot be 3rd generation (warnaa uskaa Betaa “B” kidhar jayegaa?)
  • And Since “A” is second generation, his brother F is also second generation.
  • Since A+F are in second generation, their mother “F” has to be first generation.

Update the table with this information

GenerationMaleFemaleNot sure(M/F)
1 OldestF
2 Mid agedA,E
3 YoungestB
0 (Not Sure)D(1/2)
C(1/2/3)

Atleast now we know who is male and who is female. But there is one problem: We don’t know exact generations of female C and D.
Given: D is the mother of two: one boy and one girl
Assume that mom “D” is first generation. But we already know the there are only three males in this family.

  • A+E= second generation but sons of F
  • B is son of daddy A

So we can’t put “D” is first generation (otherwise 2nd generation mein Tisraa Betaa Kidhar Se Laaoge?)
It means “D” is definitely second generation female. And corollary to that, “C” is third generation female and daughter of mommy “D”. This satisfies the condition
D is the mother of two: one boy(B)and one girl(C)
Update the table

GenerationMaleFemaleNot sure(M/F)
1 OldestDeadF
2 Mid agedA,ED
3 YoungestBC
0 (Not Sure)

Only one problem remains: Who is the husband of “D”: is it A or is it E?
Given: There is one married couple in the family at present.
Given: B is the Son of A.

From previous steps we already Concluded that: D is mother of B+C
From these three sentences we can derive that B is the son of A+D , therefore A+D are husband and wife.
And A’s brother “E” is middle-aged unmarried clown just like Patrakaar Popatlaal because of his arrogant and obnoxious attitude, no woman is interested in marrying with him.
anyways, I’m drawing this family tree from Grandson “B”’s point of view.
IAS IPS CSAT IBPS Aptitude Notes

Step-2: Run the checklist

ChecklistPass/Fail?
Men and women are in equal numberPass: 3+3
A and E are sons of FPass
D is the mother of two: one boy and one girlPass
B is the son of APass

Green light. Go on, solve the questions.

Step-3: Solve the Question

Which of the following inference can be derived from the given dataset?

  • i) A,B and C are females
  • ii) A is the husband of D
  • iii) D is the grandmother of F
  • iv) E and F are children of D

From the family tree diagram, we can see that option (ii) is correct: A is indeed the husband of D.

Do eliminate wrong options

  • In some arrangement questions “Two cases” / “two tables”/”Two family trees” may be possible.
  • So even after passing the checklist, you may still get incorrect answer; because while doing the arrangement you might have missed some minor detail so you concentrated only on one possible case. You cannot rectify this mistake with checklist alone, because checklist will pass for each of “Two possible cases.” (For example recall the circular arrangement/round table sitting case in previous article.)
  • Therefore, when you’re checking the 4 answer options, even if you get correct match in second option(ii), don’t stop just yet, you should still check whether the remaining answer option 1, 3 and 4 are incorrect or not.
Answer statementsTrue / FalseWhy?
A,B and C are femalesFalseDataset itself said A+E are sons of F. So A can’t be a female.
A is the husband of DTrueTable says so.
D is the grandmother of FFalseTable says F is saas and D is her bahu.
E and F are children of DFalseA+E are the sons of F, it is given in the question itself!
So E and F cannot be children of D!

Final answer:  A is the husband of D.

Keep a Watch on the Watch

As I had said earlier,
Out of their lack of interest, inferiority complex, many aspirants don’t practice enough aptitude sums at home.
So in the actual exam, they get stuck in 7/10 math questions = stress.
While under stress, they come across the ‘logical-arrangement’ questions. They start thinking like a defeated gambler:
I can definitely solve this arrangement; beside i couldnot tick previous 7 questions so I must solve this anyhow, no matter how much time it takes!
Problem: They end up wasting good 15-20 minutes in one dataset only. Sometimes even after investing 20 minutes in one arrangement, they may not get the final answer because they did not practice enough sums at home. That’s why

  • Practice maximum questions at Home.
  • In the examhall, always keep a watch on your wristwatch. Learn to give up the fight before it’s too late and invest that time in the remaining questions in other sections.
  • And most importantly: Don’t hate the Aptitude/Maths.
  • Competition is tough everywhere: whether you’re an aspirant of CSAT/CMAT/IBPS or CAT, so if you don’t work hard, someone else will, and then he’ll get the job/admission.
  • So don’t hate the aptitude, hate your own laziness and fix it before it’s too late. With constant practice, anyone from arts, commerce and science can master aptitude.

Mrunal recommends

  1. (free) NCERT, NIOS, TN-Books 4 History,Geo,Sci
  2. Indian Polity M.Laxmikanth (Hindi | English)
  3. Spectrum: Modern History (Hindi | English)
  4. Maths: Quantam CAT Sarvesh Kumar
  5. Objective General English SP Bakshi
  6. Word Power made Easy -Norman Lowe
  7. Topic wise Solved Paperset by Disha

28 Comments on “[Aptitude] Family Trees & Blood Relations: Logical Arrangement Made Easy”

  1. Hi Mrunal,
    Thank God , I dont know how i Reached here , But I did it, Mrunal dude you rock man, this is the way i want to read, this is the way I want somebody explain me. This is the way I will study. Nobody can stop me now. Mrunal man I really want to hug u brother for Your sincere effort . humanity exist in this bloody world. Hats off to you
    Thanks ,
    Newbie (Now much confident)

    1. hehe.. well said. i’d say the same :)

  2. your tips and trips are sure to help many. thanks for sharing.

  3. U R AN EXCELLENT TEACHER……N THE WAY YOU UNDERSTAND THE PSYCHE N MISTAKES OF A NEW COMER IS PHENOMENAL…..UR ARTICLES R WRITTEN SO VIVIDLY N DEY GRADUALLY TAKE US TO THE NEXT LEVEL……I WANNA THANK U FOR SUCH A GREAT SERVICE TO THE STUDENT COMMUNITY…..I THINK …THIS BLOG AND YOUR SPIRIT REPRESENTS WHAT WE CALL” THE NEXT BIG THING”…:)

  4. I heartly thank for giving the best aproach to solve dis kind of problem.Kindly help me the aproach to be taken when profession is also included.I have a question below-

    There is a family of 3 generations,having 8 members.there are xactly two married couples in the family and the remaining 4 members are unmarried.pat’s granddaughter,killian,is an engineering student.Laurie’s mother cathy is a lawyer,while his maternalaunt Betty is a banker.Caro’s son,Davy,is into shipping,while her son in law,jeremy,runs a fitness academywith his son.what is lauries profession?

  5. Sir please post approach for solving questions of blood relations as-pointing towards picture Harish said the person in photo is brother……

  6. Really an imaginative article.
    Thanks man.

  7. MRUNAL SIR ONE MORE ARTICLE ON BLOOD RELATION …………….PLEASE.

  8. Hi Mrunal,

    Could you please solve the family tree problem given in CSAT II– 2011.

    It is driving me crazy!

  9. A,b,c,d and e are members of the same family.there r 2fathers,2sons,2wives,3males and 2 females.the teacher was the wifecof axlawyer who was the son of a doctor.e is not a male neither also a wife of professional.c is the youngest in the family n d the eldest.b is male.how is d related to e,who r the females in the group,whose wife isthe teacher?

    1. D, E are couple (senior most- Gen 1)
      B, A are couple (gen 2)
      C is a male, single (Youngest, gen3)

      D – doctor (Male)
      B- Lawyer (Male)
      A- Teacher (F)
      E- Grandmother (F)
      C- Male

      Hence, correct answers are:
      a. Females in family ‘A,E’
      b. ‘A’ is the teacher who is the wife of ‘B’.

      1. Hi,
        How could E be the wife of D, when in question statement it is mentioned that “E is a not a male neither also a wife of professional”. If D is doctor, then how come E is wife of D.?

  10. I find coded relationships very time consuming even after practice. Does someone know an easier approach to it?

  11. Hey really usefull for learning. So many exams i was confused of this blood relation and have never arrived at the answer… You are excellent… in teaching…!!!:)

  12. grt article concept cleared

  13. Hi,

    @roopali,

    I don’t understand what wife “c” means but taken teacher c into consideration and lawyer as “a”

    it goes as follows…
    D:Male,First Generation
    E:female,First Generation

    D and E are married. D is not a professional

    Doctor (b) is male son of D.

    with lawyer (a) as son of doctor (b) and teacher (c) as his wife

    Conditions:2 fathers:-(D,B)
    2 females:-(C,E)
    3 males:-(D,A,B)
    2 wives:-(C,E)
    2 sons:-(B,A)

    Hope U will understand

  14. although,i am preparing for management exams,,,,,family tree concepts helps me a lot especially in nmat exam.
    thanking you sir

  15. I got an easier method the tree method
    do as follows
    + for male
    – for female
    for married couples
    \
    \ for sons and daughters
    for the above discussed question by Mrunal sir the diagram would be like

    (+)ED(-)
    \
    \
    (+)BC(-)
    /\
    (-)F A
    this is the best method frnds just give it a try

  16. is missing in cmnt as it is used for married couples

  17. hmmm use it btw maried couples

  18. Excellent way of explaining you saved my neck.

  19. sir how is my mother in laws’ grand daughter related to me?
    what will i consider “own daughter” or “brother in law’s daughter”
    please answer.
    thanxxx

  20. sir, there should be more questions and answers of other type based on blood relsn than given

  21. E is doctor

  22. Awesome tricks..i m loving it :)

  23. Excellent Trick sir, I have been searching for it.I have not seen any post like this . now i am very happy sir

  24. Thank you brother.You are rocking.Thank god to make me to see your page

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