Pointing to a photograph of a man, Arjun says, 'He is the son of the only son of my grandfather.' How is the man related to Arjun?
He is Arjun's brother. The only son of Arjun's (paternal) grandfather is Arjun's father, and a son of Arjun's father who is someone other than Arjun is Arjun's brother.
Explain it simply
Solve blood-relation sentences from the far end back towards the speaker, one link at a time, like tracing a family tree on WhatsApp group photos. "My grandfather's only son" collapses into a single person: Arjun's father. Then "son of my father" is either Arjun himself or his brother.
Example
Question: "He is the son of the only son of my grandfather." Who is he to Arjun?
- My grandfather's only son = my father (for a paternal grandfather, the father is his son; the word 'only' rules out uncles).
- Son of my father = me or my brother.
- Arjun is pointing at a photograph of someone else, so the man is Arjun's brother.
Related: "She is the daughter of the only daughter of my mother's mother" (spoken by a man). His mother's mother's only daughter is his mother. Her daughter is his sister.
Grandfather
|
Father (only son)
/ Arjun Man in photo -> brotherWhat to say in the interview
"I simplify from the outside in. My grandfather's only son is my father, and my father's son, other than me, is my brother. If the question allows it, I'd mention the man could be Arjun himself, but the usual intended answer is brother."
Common mistakes
- Answering 'cousin', which would need the grandfather to have more than one child.
- Working from the speaker outward instead of collapsing the phrase from the far end.