Pointing towards a man, a woman said, "His mother is the only daughter of my…
2023
Pointing towards a man, a woman said, "His mother is the only daughter of my mother." How is the woman related to the man?
Answer: A. Mother — CONCEPT: In blood-relation puzzles, a phrase like "the only daughter of X" acts as a strict pointer: if X truly has just one daughter, that phrase can be…
- A.
Mother
- B.
Grandmother
- C.
Sister
- D.
Daughter
Attempted by 4 students.
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Correct answer: A
CONCEPT: In blood-relation puzzles, a phrase like "the only daughter of X" acts as a strict pointer: if X truly has just one daughter, that phrase can be replaced with the identity of whoever is already known to be X's sole daughter -- there is no ambiguity left to resolve.
"My mother" refers to the speaker's (the woman's) own mother.
The woman states that her mother has an "only daughter" -- meaning her mother has exactly one daughter, no more.
The woman herself is a daughter of her mother, and since no second daughter is possible ("only"), that one daughter must be the woman herself.
Substituting this identity into the sentence, "His mother is [my mother's only daughter]" becomes "His mother is [the woman speaking]."
Therefore the woman speaking is directly related to the man as his mother.
CROSS-CHECK: Draw a family tree -- the woman's mother has exactly one daughter, who is the woman herself. The man's mother is defined as that one daughter. So the man's mother is the woman -- consistent, with no contradiction.