Ramakrishna said, "This girl is the wife of the grandson of my mother." How is…

Concept:

In a blood-relation puzzle, when the speaker connects a relative through an ancestor and no other sibling of the speaker is mentioned, that relative belongs to the speaker's own line -- for example, "my mother's grandson" (with no other sibling named) is the speaker's own son. Also, the wife of a man is the daughter-in-law of that man's father, which makes the father the wife's father-in-law.

Application:

1. Ramakrishna is a son of his mother, so any son of Ramakrishna is automatically a grandson of Ramakrishna's mother as well.

2. Since no other sibling of Ramakrishna is mentioned anywhere in the statement, "the grandson of my mother" must refer to Ramakrishna's own son.

3. The girl is described as the wife of this grandson, i.e., the wife of Ramakrishna's son.

4. The wife of Ramakrishna's son is Ramakrishna's daughter-in-law.

5. The father of the girl's husband is her father-in-law -- so Ramakrishna is the girl's father-in-law.

Cross-check:

The family tree confirms the chain: Ramakrishna's mother, then Ramakrishna, then Ramakrishna's son (whose wife is the girl). Reading the tree from the girl's side, her husband's father is Ramakrishna -- exactly the definition of a father-in-law.