Pointing to a boy, Ishaan said, “His mother is the only daughter of my wife’s paternal grandfather’s only son.” How is Ishaan’s father-in-law related to the boy?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Maternal grandfather
Read the chain from the end. A woman’s father is a son of her paternal grandfather; if the grandfather has only one son, that son is her father.
Ishaan’s wife’s paternal grandfather is the father of her father
Her father is a son of this man, who has only one son, so “my wife’s paternal grandfather’s only son” is the wife’s father: Ishaan’s father-in-law
Ishaan’s wife is a daughter of her father, who has only one daughter, so the boy’s mother is Ishaan’s wife
Ishaan’s father-in-law is the father of the boy’s mother: he is the boy’s maternal grandfather
Why the other options are incorrect
Option (2) Paternal grandfather — Incorrect. He is the father of the boy’s mother, not of the boy’s father.
Option (3) Father — Incorrect. He is the father of the boy’s mother, two generations above the boy.
Option (4) Maternal uncle — Incorrect. A maternal uncle is the mother’s brother; he is the mother’s father.