Blood relations for LIC AAO

Blood relation questions look like common sense, which is exactly why candidates get them wrong. The setter describes a family in fragments, and the mistake is to fill the gaps with assumptions: that a name sounds male, that "Q is the parent of R" means father, or that two people mentioned together are married. The reliable method is to draw a small tree, mark only what the question states, and read the answer off the tree.

Principles

• Gender comes only from relation words. Son, daughter, brother, sister, father, mother, husband, wife, uncle, aunt, nephew and niece state gender. Child, sibling, parent, spouse and cousin do not. Names never do.
• One level per generation. Grandparents at the top, then parents, then children.
• Standard convention: brothers and sisters share both parents, and a husband and wife are both parents of their children. Questions rarely involve step-relations unless they say so.
• If the answer depends on an unstated gender, it cannot be determined. Choose that option without hesitation.

Drawing the tree

Use the same marks every time on your rough sheet:

• Write "+" after a male and "−" after a female. Leave it blank if gender is not stated.
• Join a married couple with "=".
• Draw a vertical line from parents down to their children.
• Join siblings with a horizontal line.

Relation words at a glance

Worked examples

Example 1. A is the mother of B. B is the sister of C. C is the father of D. How is A related to D?

• A (−) is B's mother. B (−) and C are siblings, so A is also C's mother.
• C (+) is D's father.
• A is the mother of D's father. A is D's grandmother. D's gender is not given, and the question does not need it.

Example 2. Pointing to a man, a person says, "His mother is the only daughter of my mother." How is the speaker related to the man?

• If the speaker is a woman, the only daughter of her mother is herself. She is the man's mother.
• If the speaker is a man, the only daughter of his mother is his sister. He is the man's maternal uncle.
• The question does not state the speaker's gender, so the answer cannot be determined.

This is why well-set questions say "a woman says" or "a man says". When the speaker's gender is given, read it before anything else.

Example 3. K is the husband of L. M is the daughter of K. N is the brother of M. O is the father of L. How is N related to O?

• K (+) = L (−). M (−) is their daughter; N (+) is M's brother, so N is also a child of K and L.
• O (+) is L's father.
• N is the son of O's daughter. N is O's grandson.

Example 4. M is the son of N. N is the sister of O. How is O related to M?

• N (−) is M's mother. O is N's sibling.
• If O is male, O is M's maternal uncle. If female, maternal aunt.
• O's gender is not stated. Cannot be determined.

Example 5 (coded). Suppose P # Q means P is the son of Q, P @ Q means P is the wife of Q, and P & Q means P is the brother of Q. What does M # N @ O mean for M and O?

• Split at each symbol: M # N (M is the son of N) and N @ O (N is the wife of O).
• N (−) = O (+), and M (+) is N's son, so also O's son.
• M is the son of O.

Practice set

Use the codes from Example 5 where needed.

1. X is the brother of Y. Y is the daughter of Z. How is X related to Z?
2. What does R & S # T mean for R and T?
3. P is the father of Q. Q is the sister of R. R is the husband of S. How is P related to S?
4. Pointing to a boy, a woman says, "He is the son of my father's only son." How is the boy related to the woman?
5. Pointing to a girl, a man says, "She is the daughter of my mother's only son." How is the girl related to the man?
6. D is the sister of E. E is the son of F. F is the wife of G. How is G related to D?
7. Y is the brother of Z. X is the daughter of Y. Z is female. How is Z related to X?
8. What does U @ V & W mean for U and W?

Answers

1. Son. X (+) is Y's brother, so he is also Z's child.
2. R is the son of T. R (+) is S's brother; S is T's son, so R is also T's son.
3. Father-in-law. P (+) is R's father (R is Q's sibling). S is R's wife, so P is her husband's father.
4. Nephew. The woman cannot be her father's son, so his only son is her brother. The boy is her brother's son.
5. Daughter. The man's mother's only son is the man himself.
6. Father. F (−) is the wife of G, so G is male. D and E are F's children, so G is D's father.
7. Aunt (paternal aunt). Z (−) is the sister of Y, and Y is X's father.
8. U is W's sister-in-law. U (−) is V's wife, and V (+) is W's brother. U is the wife of W's brother. W's gender is not needed.

A two-minute routine

• Read the speaker's gender first in pointing questions.
• Mark + and − only from relation words, never from names.
• Draw generations on separate levels before answering.
• If two answers remain because a gender is missing, choose "cannot be determined".

What to do next

• Solve ten blood-relation questions a day this week, drawing the tree even when the question looks easy.
• Practise coded relations alongside coding–decoding, since the decoding habit is the same.
• Add blood relations to the quick-question block in your reasoning plan.