All the six members of a family, 1, 2, 3, 4, 5 and 6, live together. 2 is the daughter of 3, but 3 is not the mother of 2. 1 and 3 are a married couple. 5 is the sister of 3. 4 is the daughter of 1. 6 is the brother of 2. Who is the mother of 2?
- (a)2
- (b)1
- (c)4
- (d)5
Answer
Why
Correct — B. One clue fixes a gender, and everything else follows from it.
Rule: 2 is the daughter of 3, but 3 is not her mother — so 3 is her father.
3 is therefore male.
1 and 3 are a married couple, so 1 is the wife of 3.
2 is the daughter of 3, so 2's mother is the woman married to 3.
That woman is 1 — option (b).
Why the others are wrong
- (a)2 — 2 is the person whose mother the question asks about. Nobody is their own mother, and this option only catches a reader who has lost track of which number is the subject.
- (c)4 — 4 is the daughter of 1, which puts 4 in the same generation as 2. She is 2's sister, not a parent.
- (d)5 — 5 is the sister of 3, and 3 is 2's father, so 5 is 2's paternal aunt — the right generation but the wrong branch.
Concept
Blood-relation puzzles hide gender inside negative clues. A line like *2 is the daughter of 3, but 3 is not the mother of 2* does not look like information about 3, and it is the only line in the whole puzzle that pins 3 down as male.
Once a gender is fixed, a marriage clue converts straight into a parent. The spouse of a father is the mother of his children, and that single step answers the question.
The remaining clues place the siblings and the aunt, and none of them affects the answer.
The puzzle takes the married couple 1 and 3 to be the parents of the children named in it, which is the standard reading SSC intends. That assumption is what rules out 5, who is 3's sister, and 4, who is one generation below 1.
Key facts
- 2 is the daughter of 3 while 3 is not the mother of 2, which is what makes 3 male.
- 1 is married to 3, so 1 is the mother of 3's daughter, 2.
- 6 is the brother of 2 and 4 is the daughter of 1, so both are siblings of 2.
- 5 is the sister of 3, which makes her 2's paternal aunt.
Study next
Common traps
- Missing the negative clue that fixes 3 as the father rather than the mother.
- Picking 5 because she is in the older generation, without checking which branch she is on.
SSC writes the family as numbered members so no name can leak a gender, then buries the one gender clue in a negative. A plain-language relation chain is asked at 17 Sep 2024, 09:00, Reasoning Q.11, where G turns out to be A's wife's brother, and a coded-symbol version at 12 Sep 2024, 12:30, Reasoning Q.8.
Related PYQs
No directly related past PYQ was found.