Blood relations for SSC CGL

Blood relation questions test whether you can follow a chain of relationships without getting lost. The single most effective technique is to draw a family tree as you read, using a few simple symbols. Once the tree is on paper, the answer is usually obvious.

Relationship vocabulary

The tree method

Use a consistent notation, for example:

• + for male and − for female (or a square and a circle);
• a vertical line for parent–child;
• a horizontal line for siblings;
• a double line for husband and wife.

Place each generation on its own level: grandparents at the top, then parents, then children.

Only use genders that are stated

Names are not reliable clues to gender, and SSC questions often test exactly this. If the question doesn't state someone's gender, mark it as unknown. Where the answer depends on it, look for an option like "cannot be determined".

Worked example: A is the sibling of B. B is the son of C. How is A related to C?
A is C's child. A's gender is not given, so we cannot say "son" or "daughter".

Pointing and introducing questions

Worked example: Pointing to a photograph, a man said, "She is the daughter of my grandfather's only son." How is the woman related to him?
His grandfather's only son is his father. The woman is his father's daughter, so she is his sister.

Worked example: Introducing a man, a woman said, "His mother is the only daughter of my mother." How is the woman related to the man?
The only daughter of her mother is the speaker herself — the question tells us the speaker is a woman. So she is the man's mother.

Chains of relations

Worked example: P is the brother of Q. Q is the daughter of R. R is the wife of S. How is P related to S?
Q is R's daughter; R is S's wife, so S is Q's father. P is Q's brother, so P is S's son.

Coded relations

Worked example: A + B means A is the father of B; A − B means A is the wife of B; A × B means A is the brother of B; A ÷ B means A is the daughter of B. What does P ÷ Q + R × S mean for P and S?
P ÷ Q: P is Q's daughter. Q + R: Q is R's father. R × S: R is S's brother. So Q is the father of P, R and S; P is Q's daughter, so P is S's sister.

Generation counting

In long chains, count generations: grandparents (+2), parents (+1), self (0), children (−1). This quickly tells you whether the answer is an uncle, a cousin or a nephew.

Common traps

Practice

1. X is the son of Y. Y is the sister of Z. How is Z related to X?
2. Pointing to a boy, a woman said, "He is the son of the only son of my father." How is the boy related to her?
3. A is the father of B. C is the mother of A. How is C related to B?
4. M is the brother of N. N is the sister of O. O is the son of P. How is M related to P?
5. If A + B means A is the mother of B, and A × B means A is the husband of B, what does P × Q + R mean?

Answers: 1. Z is X's maternal uncle or aunt (Z's gender is not given). 2. Nephew (the only son of her father is her brother). 3. Grandmother. 4. Son. 5. P is the husband of Q, and Q is the mother of R, so P is R's father.