SSC CGL 2025 Tier-I · 15 September 2025, Shift 2 · General Intelligence and Reasoning · Question 5 of 100

We transcribed this text from the pictures on a candidate's response sheet for this shift; the answer is the key SSC colour-marked on that sheet. Solution last reviewed 11 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. From 2025 the candidate response sheet prints every question and option as a picture, so the text here is transcribed from those pictures for this shift and checked against them independently; where the layout carries meaning, the picture is shown as well. Each answer is the key SSC colour-marked on that sheet. SSC released a tentative key for challenge and later its final one, both only to candidates behind a login, and the sheet does not say which of the two it carries. The solutions are written by UnlockIAS.

A says, “My mother’s husband's only son is B.” How is A related to B? (A and B are not the same)

(a)Sister
(b)Son
(c)Father
(d)Wife

Answer

Why

Correct — A.
Rule: resolve the chain one link at a time, starting from A.

A's mother's husband = A's father.
His only son = B.

A is his child too, but not his son, since B is the only son and A is not B.
So A is his daughter, and B's sister → option (a).

Why the others are wrong

(b)
Son — Son would put A a generation below B, yet A and B share a father. And B is that father's only son, so A is not a son of his either.
(c)
Father — Father would put A a generation above B. A's mother's husband is A's own father, and his son is B, so A and B are siblings.
(d)
Wife — Wife would need A and B to be a couple. A's father is B's father, so they are siblings, not husband and wife.

Concept

A spoken blood-relation puzzle is a chain of possessives. Replace each link with the plain relation it names: mother's husband is simply father.

Then apply the limits the question adds. 'Only son' means the father has no other son, and '(A and B are not the same)' stops A from being that son. What is left is a daughter of the same father: B's sister.

Without the note in brackets, A could be the only son speaking of himself. The note rules that out, and with it any answer that makes A male.

Key facts

Mother's husband is read as father, and father's wife as mother.
'Only son' means the parent has no other son.
Two children of the same father are siblings: brother or sister by the child's gender.

Study next

Chains that loop back to the speaker, such as 'my father's only son'Pointing-to-a-person blood-relation puzzlesCoded blood relations, where a symbol such as + stands for 'is the mother of'

Common traps

Missing the note in brackets and treating A as the only son
Choosing Son because the sentence ends on the word son

12 Sep 2025, 09:00, Reasoning Q.24 opens with the same chain, 'My mother's husband's only son', but there a man is speaking, so the only son is the speaker himself, and he is keyed as your Father.

14 Sep 2025, 09:00, Reasoning Q.17 runs the chain from the listener's side: 'Your father's wife's son is my brother', keyed Sibling.

Related PYQs

No directly related past PYQ was found.

Topic: Problem Solving — all 74 SSC CGL questions on it, every solved shift.