Pointing to a lady, a girl said, "She is the daughter-in-law of the grandmother of my father's only son." How is the lady related to the girl?

Introduction / Context:

This question tests the ability to decode a slightly long description of family relations and identify how a particular lady is related to the girl who is speaking. The phrase “daughter-in-law of the grandmother of my father's only son” must be interpreted step by step to avoid confusion. Such questions are quite common in bank and SSC aptitude exams.

Given Data / Assumptions:

• The speaker is a girl.
• She says about a lady: “She is the daughter-in-law of the grandmother of my father's only son.”
• “My father's only son” refers to the single male child of her father.
• We assume standard, straightforward family relationships without step-relations unless explicitly mentioned.

Concept / Approach:

The description involves three levels: the girl and her father, her father's only son, and that boy's grandmother. Then we look at who is the daughter-in-law of that grandmother. The main trick is to correctly understand who “my father's only son” is, and whose grandmother is being referred to. After that, identifying the daughter-in-law of that grandmother reveals whether the lady is the girl's mother or some other female relative.

Step-by-Step Solution:

Verification / Alternative check:

We can substitute labels: grandmother = G, her son = F (the girl's father), and F's wife = M (the girl's mother). M is a daughter-in-law of G. The girl is a child of F and M. The described lady therefore matches the position of the girl's mother. Any other daughter-in-law of G, such as an aunt, is not singled out in the puzzle, and typical solutions treat the direct parent-child link as the intended one.

Why Other Options Are Wrong:

“Sister-in-law” would be the wife of the girl's brother or the sister of her husband, not the daughter-in-law of her grandmother.

“Aunt” could be another daughter-in-law of the grandmother, but the question structure in standard reasoning books usually takes this configuration as describing the girl's mother, not her aunt.

“Can't be determined” is incorrect at exam level because the intended standard assumption points to the direct relationship of mother and daughter.

Common Pitfalls:

A common mistake is to start combining too many hypothetical relatives (multiple sons of the grandmother) and conclude that the answer is indeterminate. In typical test settings, unless multiple possibilities are explicitly highlighted, puzzles like this are meant to be solved using the most direct and obvious family links.

Final Answer:

The lady is related to the girl as her mother.