Blood Relations

Blood relation problems give you clues in a chain. The safest method is always to draw a family tree — boxes for people, lines for parent-child, = for married couples.

Symbols:

• △ = male | ○ = female | △=○ = married couple | vertical line = parent-child | horizontal = siblings

Example 1 (simple chain):

"A's father is B's son. C is B's father. How is A related to C?"

Build the tree:

C
└── B (C's son)
    └── (B's son) = A's father
        └── A

So: C → B → (A's father) → A C is A's great-grandfather.

Example 2 (gender trap):

"Pointing to a photograph, Rekha said: 'He is the only son of my grandmother's only daughter.' How is the person in the photo related to Rekha?"

Rekha's grandmother → only daughter = Rekha's mother. Mother's only son = Rekha's brother. Answer: Brother

Example 3 (coded relations):

A + B means A is the father of B A - B means A is the mother of B A × B means A is the brother of B A ÷ B means A is the sister of B

If P + Q - R, how is P related to R? P is Q's father → Q is R's mother → R is P's grandchild (specifically granddaughter since Q is mother).

1. Identify all people mentioned (assign letters if needed)
2. Draw the tree — don't try to solve in your head
3. Resolve gender first — many tricks involve gender ambiguity
4. Check from the question's perspective — "A is related to B" vs "B is related to A"

1. A is B's sister. B is C's mother. C is D's father. How is A related to D?

2. "That woman is the mother of my daughter's husband's sister." What is the woman to you?

3. Pointing to a man, a woman says: "His mother is the only daughter of my mother." How is the woman related to the man?

4. P is Q's brother. Q is R's sister. R is S's father. How is P related to S?

5. Stretch: In a family, there are 6 members A, B, C, D, E and F. A and B are married. D is A's son and E's brother. C is B's daughter-in-law. F is E's grandfather. Who is B's father-in-law?