A family consists of six members P, Q, R, S, T and U. There are two married couples. Q is a doctor and the father of T. U is the grandfather of R and is a contractor. S is the grandmother of T and is a housewife. There is one doctor, one contractor, one nurse, one housewife and two students in the family. Who is the sister of T?

Introduction / Context:

This is a complex family-relation and logic puzzle that blends professions (doctor, contractor, nurse, housewife, students) with generational and gender information. You must reconstruct the family tree, identify the two married couples, and then determine which member is the sister of T. These types of questions appear frequently in competitive exams and require careful, systematic reasoning.

Given Data / Assumptions:

• Family members: P, Q, R, S, T, U (six in total).
• There are exactly two married couples.
• Q is a doctor and the father of T.
• U is the grandfather of R and is a contractor.
• S is the grandmother of T and is a housewife.
• Professions: one doctor (Q), one contractor (U), one nurse, one housewife (S) and two students.
• We must find who is the sister of T.

Concept / Approach:

We first place the grandparents (U and S) and parents (including Q) into a generational structure. The clue that S is the grandmother of T and U is the grandfather of R strongly suggests that U and S are one married couple and grandparents in general. Q, as the father of T, belongs to the parent generation. The remaining family members (P and R) must then be distributed among spouse and children roles in a way that respects the two-couple limit and the profession constraints. From this structure, we infer who T's sister is.

Step-by-Step Solution:

Verification / Alternative check:

Assign roles concretely: U (grandfather, contractor) married to S (grandmother, housewife). Their son Q (doctor) marries P (nurse or student). Q and P have two children: T and R, both students. This arrangement satisfies all clues: U is grandfather of R; S is grandmother of T; Q is father of T; there are two married couples (U–S, Q–P); one doctor (Q), one contractor (U), one housewife (S), one nurse or student (P), and two students (R and T). In this family, R is T's sibling and, under standard naming assumptions, T's sister.

Why Other Options Are Wrong:

U cannot be the sister of T, because U is explicitly the grandfather.

T obviously cannot be his or her own sister.

"None of these" is incorrect because R fits both the generational level and sibling role required by the question.

Common Pitfalls:

One common error is to treat R as a parent or as a member of the older generation, which conflicts with "U is the grandfather of R". Another mistake is to forget the "two married couples" constraint and attempt to create an extra couple. Keeping track of how many spouses are allowed and verifying the profession counts at the end helps prevent such mis-assignments.

Final Answer:

The sister of T is R.