P has a son and a daughter. S is the mother of T. S is R's spouse. Q and R are children of P. Then how is Q related to S? (a) Q is a sister of S (b) Q is a daughter of S (c) Q is the mother of S (d) Q is a sister of the husband of S

UPSC Prelims 2026 · CSAT Paper 2 · Set DLogical ReasoningQ 24 / 80

UPSC Prelims 2026 CSAT Paper 2 — Question 24

Question

P has a son and a daughter. S is the mother of T. S is R's spouse. Q and R are children of P. Then how is Q related to S?

(a)Q is a sister of S
(b)Q is a daughter of S
(c)Q is the mother of S
(d)Q is a sister of the husband of S

UnlockIAS answer: (d)Q is a sister of the husband of S

Solution

S (a mother) is R's spouse, so R is male — P's son. Q is P's other child (the daughter), hence Q is R's sister, i.e. a sister of the husband of S.

UnlockIAS expert key, prepared 24 May 2026 and cross-verified by re-deriving the answer — this is our key. The official UPSC provisional key has been released.

Section

Logical Reasoning

Topic Reference

Logical Reasoning — Blood relations

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