Introduction

Consider the information below:

Pointing to a girl, Sam said, “She is the only daughter of my mother-in-law.”

If we analyze the information provided above, we can infer that the girl is Sam’s wife. In Blood Relations problems, we figure out the relationship among different members of a family based on the information provided to us. To solve these problems, it is necessary that we have adequate knowledge of different relations in a family.

Some Common Relations

Let’s see some common relations in a family:

1. Grandfather’s or Grandmother’s only son: Father

2. Grandfather’s or Grandmother’s son: Father or Uncle

3. Father’s father: Grandfather

4. Father’s mother: Grandmother

5. Father’s son: Brother

6. Father’s daughter: Sister

7. Father’s wife: mother

8. Grandfather’s or Grandmother’s only daughter-in-law: mother

9. Brother’s wife or Wife’s sister or Husband’s sister: Sister-in-law

10. Sister’s husband or Wife’s brother or Husband’s brother: Brother-in-law

11. Father’s brother or brother-in-law: Uncle

12. Brother’s or Sister’s daughter: Neice

13. Brother’s or Sister’s son: Nephew

14. Uncle or Aunt’s son or daughter: Cousin

15. Mother’s Father: Maternal Grandfather

16. Mother’s mother: Maternal Grandmother

17. Mother’s brother: Maternal Uncle

18. Mother’s sister: Maternal Aunt

Blood Relation Tree

The best way to solve these problems is to create a Blood Relation Tree (Diagram to represent the relations) and then visualize the relationship between different members of a family. To do so, we represent the relations with the help of symbols. 

Here, we have listed the symbols we have used in this course but you can create your own set of symbols as well.

1. A is a male:Symbol to represent A is a male

 

2. A is a female:

Symbol to represent A is a female

3. A and B are married to each other:

Symbol to represent A and B are married to each other

4. A and B are siblings:

Symbol to represent A and B are siblings

5. A is the child of B or B is the parent of A:

Symbol to represent A is the child of B or B is the parent of A

Your Turn:

Let’s practice what we have learned. 

Blood Relations Question 1: Q’s mother is the sister of A and daughter of B and D is the daughter of A and sister of P who is a female. How is P related to B?

A. Sister

B. Daughter

C. Daughter’s daughter

D. Daughter’s mother

E. Granddaughter

To solve this problem, let’s first draw the blood relation tree.

-> Q’s mother is the sister of A and daughter of B

We have represented Q’s mother with (-) since she is a female. We don’t know the genders of Q, A and B from this piece of information.

-> D is the daughter of A and sister of P who is a female.

Practice Exercise 1: Blood Relation Tree Complete Diagram

This completes our blood relation tree as per the information provided in the question. Note that we don’t know the genders of B, A, and Q.

Clearly, P is the granddaughter of B. Since the gender of A is not known, we can’t say whether P is B’s son’s daughter or B’s daughter’s daughter. So, E is the only correct option.

Blood Relations Question 2: In Practice Exercise 1, how is Q related to B?

A. Daughter

B. Son

C. Granddaughter

D. Grandson

E. Data Inadequate

Since we don’t know the gender of Q, we can’t say whether Q is the grandson or the granddaughter of B. So, E is the correct option.

Blood Relations Question 3: Pointing to a boy, Rohit said, “He is the son of my grandfather’s only child who is a male.” How is the boy related to Rohit?

Blood Relation Tree:

Blood Relation Tree: Practice Exercise 3

Clearly, the boy is Rohit’s brother.

Blood Relations Question 4: Pointing to a man in the photograph, Nikita said, “His son’s mother is the daughter-in-law of my mother.” How is Nikita related to the man?

Let’s draw the blood relation tree: 

-> Man’s son’s mother should be his wife.

Practice Exercise 4: Blood Relation Tree Part - 1

-> Now man’s wife is the daughter-in-law of Nikita’s mother.

Practice Exercise 4: Blood Relation Tree Complete Diagram

From the diagram above, we can see that Nikita is the man’s sister.

Blood Relations Question 5: Introducing a boy, Emma said, “His father is the only son of my mother-in-law.” How is Emma related to the boy?

Let’s draw the blood relation tree: 

-> Boy’s father is the son of Emma’s mother-in-lawPractice Exercise 5: Blood Relation Tree Part - 1

-> Obviously, Emma is boy’s father’s wife.

Practice Exercise 5: Blood Relation Tree Complete Diagram

From the diagram above, we can see that Emma is the mother of the boy.

Blood Relations Question 6: Pointing to a lady, Neeru said, “She is the sister of my uncle’s daughter.” How is the lady related to Neeru?

Blood Relation Tree: 

Practice Exercise 6: Blood Relation Tree

Clearly, the lady is Neeru’s Cousin.