Math & Beyond

Blood Relations

28th Sep '2077 views1 mins read


28 September 2020

Reading Time: 4 Minutes


Blood relations is one of the trickiest topics in logical reasoning. But if studied in the right manner and solved with the help of a family tree, it becomes quite easy to solve.

So let's first understand the meaning of blood relation!

Relation as we know is the connection between any two things or between any two persons. So when speaking of blood relation, it means the connection between two people by blood or basically by birth.

In addition to this, two people or two families get connected by marriage, hence the relations which are created by marriage are also considered as blood relations.

What is a Family Tree?

A tree as we know has roots firmly grounded and then it has its stem which branches out and gets leaves in it. 

Same is the case with a family tree, wherein we can imagine our ancestors as the roots and then their children and grandchildren and so on act as branches and leaves.

Family Tree a pictorial or visual representation of our lineage. With the help of a family tree, it not only gives us a better understanding of our lineage but also helps us understand our relationship with different people who have common ancestors.

parent daughter

Basic Terms used in Blood Relations 

Parents: Mother and father.
Children: Son or Daughter
Siblings: Brother or Sister( of the same parents)
Spouse: Husband or wife.
Aunt: Aunt means father’s sister, mother’s sister, father’s brother’s wife or mother’s brother’s wife.
Uncle: Uncle means father’s brother, Mother’s brother, Father's sister’s husband, mother’s sister’s husband.
Niece: Brother’s and sister’s daughter.
Nephew: Brother’s and sister’s son.
Cousin: Children of aunt and uncle.
Father in-law: Father of spouse.
Mother in-law: Mother of Spouse.
Sister in-law: Sister of spouse, wife of brother
Co-sister: Wife of spouse’s brother.
Brother in-law: Brother of spouse, husband of sister
Co- brother: husband of spouse’s sister.
Maternal: Relations or family members who are from mother’s side.
Paternal: Relations or family members who are from father’s side.

family photos

Example Problems

Example 1: A family consists of five members B, C, E, F and G. C is the son of G but G is not the mother of C, E and G are married couple. B is the brother of G. F is the daughter of E. Who is the brother-in-law of E?
(A) F      (B) G      (C) B      (D) None of these


(C) B

With the given information we will draw the family tree.

family tree

From the family tree drawn, we get to know that the brother-in-law of E is B.

Equation Based questions

Example 2: A + B means B is the brother of A.
A × B means B is the husband of A.
A – B means A is the mother of B.
A % B means A is the father of B.
How is Q related to T from the expression "Q-P+R%T"?
(A) Grandmother         (B) Mother           (C) Aunt           (D) Niece 


(A) Grandmother

Solution: From the given information we simplify the expression "Q-P+R%T"
Q is the mother of P
P is the brother of R
R is the father of T

family tree drawing

From the family tree drawn we can say that the Q is the grandmother of T.

Pointing to a person type problems

Example 3: Pointing to a man, a woman said, "His mother is the only daughter of my mother". How is the woman related to the man?
(A) Aunt         (B) Sister         (C) Cousin     (D) Mother



(D) Mother

Solution: We trace the given statement backwards; Woman’s mother has only one daughter, which means the woman herself. So the man’s mother is the woman herself and hence the correct answer is option D.

Practice Problems

Question 1: Introducing a man, a woman says, “His wife is the only daughter of my father”. How is the man related to the woman?
(A) Brother        (B) Father-in-law        (C) Maternal uncle       (D) Husband 

Question 2: If ‘A×B’ means that A is the sister of B, ‘A÷B’ means that A is the daughter of B, ‘A–B’ means that A is the son of B, then how is P related to S in relationship P – Q × R ÷ S?
(A) Brother      (B) Son      (C) Grandson       (D) None of these 

Question 3: A visits his brother P who stays with their father Q, mother S and grandfather R, P has two children, B and C. B's husband is X and C's wife is Y. C's son T welcomes A on his visit. How is B related to Q?
(A) Grand-daughter      (B) Grandson     (C) Son          (D) Daughter 

Question 4: A's Son B is married to C whose sister D is married to E, who is the brother of B. How is C related to E?
(A) Sister-in-law          (B) Sister      (C) Daughter         (D) Cousin


1. (D)       2. (C)       3. (A)       4. (A)


Blood relations is one of the most important topics in logical reasoning.

Two fundamental requisites for this topic are knowledge of terms associated with various types of relationships and the understanding of sketching a family tree and to be able to draw information out of it.

Perfection and confidence will only be observed when a student does rigorous practice of these types of questions extensively!

Frequently Asked Questions (FAQs)

What is blood relations in reasoning?

Blood relation shows the different relations among the members of a family. Based on the information given, you are required to find the relation between particular members of the family.

-Written by Neha Chauhan, Cuemath Teacher

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