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How To Solve Blood Relation Problems Fast?

This article will help with tricks to solve blood relation problems that are common in CAT as well as many competitive examinations

this is an image of Solve Blood Relation Problems Fast With These Tricks

Do blood relation problems scare you? Blood relations problems are an important part of the logical reasoning part of the question paper as well as practice. This is crucial not only for CAT but for other competitive exams as well. You can find 2-3 questions on the test. But sometimes it may come as comprehension of 4 questions. Here will learn about tricks that will help you solve any blood relation problem quickly.


Why are blood relation problems important?


Blood relation problems are difficult for many students. We often see that in our modern society, most families are nuclear families and we rarely see a joint family anymore. This new family structure has made visualizing complex relationships difficult for our generation. This fact is taken advantage of by the CAT question papers.


Why is it important to know blood relation problems tricks?


Blood relation problems can take a lot of time. To save time, we recommend you to memorize this list. Any CAT topper knows how important it is to save time during the exam.


Let us first define different terms for clarity. If you can memorize this list, you may be able to solve the blood relation problems questions faster.


StatementDirect relation
Father of grandfather or grandmotherGreat grandfather
Mother of grandfather or grandmotherGreat grandmother
Father of father or motherGrandfather
Mother of father or motherGrandmother
Wife of grandfatherGrandmother
Husband of grandmotherGrandfather
Father-in-law of father/motherGrandfather
Mother-in-law of father/motherGrandmother
Husband of motherFather
Only daughter-in-law of father’s father/father’s motherMother
Second wife of the fatherStepmother
Brother of fatherUncle
Brother of motherMaternal Uncle
Sister of fatherAunt
Sister of motherMaternal Aunt
Husband of auntUncle
Wife of uncleAunt
Son of grandfather/grandmotherFather/Uncle
Daughter of father-in-law/mother-in-law of fatherMother/Aunt
Father of wife/husbandFather-in-law
Mother of wife/husbandMother-in-law
Children of the same parentsSiblings
Father’s/Mother’s only son/daughterOneself
Son of father or motherBrother
Daughter of father or motherSister
Son of the second wife of the fatherStepbrother
Daughter of the second wife of the fatherStepsister
Son/daughter of uncle/auntCousin
Brother of husband or wifeBrother-in-law
Sister of husband or wifeSister-in-law
Husband of sister/sister-in-lawBrother-in-law
Son of fatherOneself/Brother
Mother of son/daughterOneself/Wife
Father of daughter/sonOneself/husband
Son of the son of grandmother/grandfatherBrother/Oneself/Cousin
Daughter of the son of grandmother/ grandfatherCousin/Oneself


Son of brother or sisterNephew
Daughter of brother/sisterNiece
Grandson of father/motherSon/Nephew
Granddaughter of father/motherDaughter or Niece
Husband of daughterSon-in-law
Wife of brother/brother-in-lawSister-in-law
Wife of sonDaughter-in-law
Son of Son/DaughterGrandson
Daughter of son/DaughterGranddaughter
Son’s/Daughter’s grandsonGreat Grandson
Son’s/Daughter’s granddaughterGreat-granddaughter


The questions on blood relations are mostly of the following 3 types

  • Statement-based
  • Puzzle-based
  • Code-based


In this article, we will explain the different ways and techniques to solve these blood relation problems.


Check out our list of Top CAT Coaching Institutes In Kolkata 


Statement-Based Questions


The blood relation problems in the statement-based category of blood relation problems are usually a dialogue or a conversation going on between two people. On the basis of the dialogue, you need to find useful information to answer the questions. Here is one example of this type of question.


Ramesh said to Suresh.” The boy playing is the younger of the two brothers of the daughter of my father’s wife”. Then how the boy playing football is related to Ramesh?


Pointing to a man standing in the photograph the woman said, “His brother’s father is the only son of my grandfather”. What is the woman to that man in that photograph?


  1. Mother
  2. Daughter
  3. Aunt
  4. Sister
  5. Grandmother


The trick to solving these problems is going back through the statement. This involves making sense of the last statement and proceed towards the beginning.


For example, if it’s given that he is the son of the father of the daughter of my grandfather, then we start with the last information in the statement: ‘Grandfather’s daughter’. Now, Grandfather’s daughter is called Aunt (father’s sister). Now, the father of my grandfather’s daughter becomes the ‘father of my aunt’ hence grandfather. Therefore, the son of my grandfather is either my father or an uncle.


Here are a few other examples:


Ex: If Amit says, “The mother of Vishal is the only daughter of my mother”, how is Amit related to Ravi?

  1. Father
  2. Brother
  3. Grandfather
  4. None of these


Sol. The only daughter of Amit’s mother Amit’s sister.


So, Vishal’s mother is Amit’s sister (or)


Amit is the brother of Vishal’s mother i.e. Vishal’s maternal uncle.


Ex: If A is the brother of the son of B’s son, how is A related to B?

  1. Grandson
  2. Brother
  3. Son
  4. Cousin


Sol. The son of B’s son = Grandson;


The brother of B’s grandson = B’s grandson.


So A is B’s grandson.


Ex: Rosie told Meena, “The girl I met yesterday at the mall was the youngest daughter of the brother–in–law of the mother of my friend.” What is the girl’s relation to Rosie’s friend?


  1. Friend
  2. Cousin
  3. Daughter
  4. Niece


Sol. Daughter of brother–in–law = Niece;


Mother’s niece = Cousin.


So, the girl mentioned is the cousin of Rosie’s friend.


Ex: Pointing towards a man, Ajit said, “His only brother is the dad of my daughter’s dad.” How is the man related to Ajit?

  1. Father
  2. Grandfather
  3. Brother–in–law
  4. Uncle


Sol. Father of Ajit’s daughter’s father – Ajit’s father.


So, the man’s brother is Ajit’s father or the man is the brother of Ajit’s father i.e., Ajit’s uncle.


Ex: A girl introduced a boy as the son of the brother of her mother. How is the boy related to the girl?


  1. Son
  2. Cousin
  3. Grandson
  4. Uncle


Sol. The brother of mother = Uncle;


Son of uncle = Cousin.


Puzzle-Based Questions


In the puzzle-based questions, usually, information is given and questions based on this information follow. The best technique to solve these types of questions is to draw family tree diagrams.


You can draw the family tree diagrams in the following fashion. It’s better that you follow a convention that will instantly tell you what line or shape means what. For example,


  • Use vertical lines ‘ | ‘ to represent parent-child relationships.
  • Use horizontal lines like ‘—-’ to represent a marriage.
  • Let dashed lines ‘- – – -’ represent sibling relationships. It may be better to not represent sibling relationships as it is directly inferred and may make the diagram look complex.
  • Represent gender by using a + sign (male) and – sign (female).
  • You can use a question mark(?) or an exclamation mark(!) for the information that is missing.


It is better to memorize the conventions. That would make your calculations faster with practice. 


Example: There are six family members- U, V, W, X, Y, and Z. U is married to V. U is a male. W has only one son, X, and W is the brother of U. Now, Y is the sister of X. V is the daughter-in-law of Z, whose husband has died.


How is U related to Z?

  1. Mother
  2. Sister
  3. Sister-in-law
  4. Mother-in-law
  5. None of these

What is the relation of Y to Z?

  1. Daughter
  2. Aunt
  3. Mother
  4. Cousin
  5. Sister

What is W to V?

  1. Brother
  2. Nephew
  3. Brother-in-law
  4. Son-in-law
  5. None of these

How many members of the family are male?

  1. 2
  2. 3
  3. 4
  4. 5
  5. 1

To solve these type of questions


  • First, read through the data once.
  • Note the useful information in points
  • Start drawing the family tree. It’s easier to find one parent-child relation and then draw around it. Relationships like grandfather-grandson are not good relationships to start with.
  • Make additions to the diagram with every piece of information. Try not to make another diagram because then it will be another task to connect both diagrams and you’ll end up wasting time. 
  • With the help of the complete diagram, answer the questions.


Now let’s solve the problem given above


Sol: The first sentence gives an idea of the family but mentions no relationship, but all other lines are actual information. As mentioned above it’s better, to begin with, the parent-child relationships. We find that the third sentence mentions a parent-child relationship i.e. X is the only son of W who’s a brother of U. Therefore, the diagram is as follows


Now we should look at all the information available. It tells more about U, X, or W. The second line tells us more about U. So, we’ll depict that in the diagram.                        


Now we shall add the leftover information and the one that fits the most in the current diagram is the relationship between X and Y.


We have almost completed our tree diagram by using the final information which is about Z who is a female since it is told that her husband had died. And V is her daughter-in-law. Therefore, she’s the mother of U and W.


We have seen an example of a blood relation puzzle. Once you draw the diagram, you can answer any question. Other blood relation puzzles have to be solved in these steps only.


Let’s consider another example of such type of questions.


Ex) X and Y are married and have two sons A and C. A marries B and C marries D. A and B have two sons and C and D have two daughters. X and Y are the grandparents of a, c, b, and d. Answer the following questions:


Q 1: If it’s given that c is a boy and d is a girl, then find out who is an uncle of c?


Answer: It is given, d is a girl that means d is the daughter of C and D. Also c is a boy, he would be the son of A and B. Thus as C is another one of the sons of X and Y, hence, the uncle of c is C.


Q 2: What is the relation between A and D?


Answer: Since it is given that A and C are brothers and also that D is married to C, D is the partner of A’s brother.


Ex) A, B, C, D are sitting on the edge of a circle, in random order. They are all related to P sitting in the center. P’s uncle is A. B’s father is P. C is the daughter of P and D. And C is P’s wife. Answer the following:


Q 1: Name the relation between B and D?


Answer: P’s wife is D and B’s father is P. Therefore, B’s mother is D.


Q 2: How is C related to B?


Answer: C is P’s daughter and P is the B’s father. Hence, B and C are siblings.


Ex:  A family consists of 6 members A, B, C, X, Y, Z.  Q is the son of C but C is not the mother of B. A and C are married couples. Y is the brother of C, X is the daughter of A. Z is the brother of A.


Questions :

  1. Who is the brother-in-law of C?
  2. How many female members are there in the family?
  3. What is B’s relation to X?
  4. How is Y related to A?



 Let us first draw the family tree diagram with the given information

  1. B is the son of C. draw this one with a thick line ‘ | ‘. Both are male so take as’+’.
  2. Use ‘ —- ‘ between A and C in the same row, because they are a couple.
  3. Add Y to C with a dotted line ‘- – – -’ in the same row.
  4. Add X to A with a line down to a different row.  Here, X is ‘ | ‘.
  5. Add Z to A and mark Z as ‘+’.
  6. So, B and X are siblings (brother and sister).

Code-Based Questions


Code-based blood relation problems are another favorite of exams like CAT. We again recommend memorizing the chart above so you can save time while solving these types of questions.


In this type of question, relationships are represented by specific codes or symbols like +, –, /, *. You need to decode the statement. In other words, you have to make sense of the relationship based on the code system. It is also a good idea to represent the relations in a diagrammatic manner for easy comprehension. 


In the code equation, it is better to solve the code from the last letter, just like in the previous type of puzzle-based questions.



If P+Q means P is the husband of Q, P/Q says that P is the sister of Q, P*Q says P is the son of Q. Then what is D to A in D*B+C/A?


Solution :


 C/A               – C is the sister of Q.

 B+C/A          – B is the brother in law of A 

 D*B+C/A     – D is the nephew of A (The sister’s husband’s son means sister’s own son i.e. nephew).


So, the answer is a Nephew.


Example: P + Q means P is the brother of Q; P – Q means P is the mother of Q and P * Q means P is the sister of Q. Which of the following means M is the maternal uncle of R?


Solution: M is the maternal uncle of R means M is the brother of the mother (say K) of R i.e. M + K – R.


Example: Q1. If ‘X + Y’ means that X is the mother of Z,


 ‘X ÷ Y’ means that X is the brother of Y,

 ‘X × Y’ implies X is the son of Y,

 ‘X – Y’ means that X is the sister of Y,


Which of the following means that C is the sister of D?


(a) C – X ÷ D

(b) X + D ÷ C

(c) D × X– C

(d) D – C × X


Ans (a)


C – X ÷ D can be drawn diagrammatically by using the given information:

‘C – X’ means that C is the sister of X

‘X ÷ D’ means that X is the brother of D.

As C is the sister of X & X is the brother of D, we can say C is the sister of D


Example: If ‘P + Q’ means P is the father of Q,

 ‘P × Q’ means P is the brother of Q,

 ‘P – Q’ means P is the mother of Q,

Then which of the following is definitely true about Z– X+ Y?

(a) Y is the son of X

(b) X is the son of Z

(c) Y is the father of X

(d) Z is the mother of Y


Ans. (b)

‘Z – X’ means Z is the mother of X,

‘X + Y’ means X is the father of Y.

As Z is the mother of X and X is the father of Y, we can definitely say X is the son of Z.


It is recommended that you solve as many blood relation problems like these using these tricks, so you develop speed and get a hold of these principles.


At IIMSKILLS, we offer online CAT coaching. Here you’ll get many more tricks and tips like this that can be crucial in your CAT performance.

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Gaurav is a Content Writer at IIM Skills. He has a B.Tech. degree but then he switched to the creative side by doing his master's in advertising and public relations. Gaurav is also a part-time blogger and graphic designer currently living in Mumbai

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