How is my father's mother's only daughter-in-law's daughter's father related to me?

Introduction / Context:

This question looks intimidating because of the long chain of possessives: "my father's mother's only daughter-in-law's daughter's father". However, it is built from common family roles and can be simplified step by step. The final relationship turns out to be very familiar—the person described is simply the speaker's father.

Given Data / Assumptions:

• The speaker is referring to several relatives in a chain.
• "My father's mother" is the speaker's paternal grandmother.
• "My father's mother's only daughter-in-law" is the only woman married to one of the grandmother's sons.
• That daughter-in-law has a daughter, whose father is the person we are analysing.
• We assume the usual simple family where the grandmother has one married son (the speaker's father) to make "only daughter-in-law" meaningful.

Concept / Approach:

The method is to decode the phrase from left to right, but understanding each step in small chunks. We start by identifying the grandmother, then her only daughter-in-law, then that daughter-in-law's daughter, and finally the father of that daughter. If the only daughter-in-law is the speaker's mother, then the father of her daughter is the speaker's father. This gives us the final relationship.

Step-by-Step Solution:

Verification / Alternative check:

Let F be the speaker's father, M be the mother, and G be the paternal grandmother. G has a single daughter-in-law M, married to F. M's daughter D is a child of F and M. The father of D is F, the same person as the speaker's father. Whether the speaker is D herself or D's sibling does not affect the fact that the father in this chain is F, the speaker's father. Thus the identification is robust.

Why Other Options Are Wrong:

The person cannot be the speaker's son or son-in-law, as the chain runs upwards to grandmother-level and then back down to a parent, not to a younger generation.

"Uncle" would indicate a sibling of a parent, but the chain clearly identifies the spouse of the grandmother's son, leading back to the parent, not sideways to a sibling of a parent.

Common Pitfalls:

A common mistake is to get lost in the repeated "of" phrases and misread "my father's mother's only daughter-in-law" as someone outside the immediate nuclear family. In typical reasoning questions, "only daughter-in-law" of the grandmother is the mother of the speaker, and the daughter of that mother has the same father for all siblings. Simplifying the chain stepwise and substituting labels like G, M, F makes these puzzles much more manageable.

Final Answer:

The person described is the speaker's father.