"His mother is the only daughter of my father/mother" (a woman speaks): how is the man related to her

The same question, asked 2 times: 12 Sep 2025 S1*, 15 Sep 2025 S3. Every wording below, oldest first.

Try each one first, then open its answer.

Question 1
12 Sep 2025 S1
22 $Pointing to a man, a woman said, "His mother is the only daughter of my father." How is the man related to the woman?$
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Question 2
15 Sep 2025 S3
24 $Looking at a man, a woman said, ""His mother is the only daughter of my mother."" How is the man related to the woman?$
Tap an option to check your answer.