SSC CGL 2025 Tier-I · 17 September 2025, Shift 2 · General Intelligence and Reasoning · Question 8 of 99

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 13 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.

Find the odd one out:

(a)6 # 2 = 12
(b)5 # 3 = 15
(c)4 # 4 = 16
(d)7 # 1 = 21

Answer

Why

Correct — D.
Rule: a # b = a × b.

6 # 2: 6 × 2 = 12, as given
5 # 3: 5 × 3 = 15, as given
4 # 4: 4 × 4 = 16, as given
7 # 1: 7 × 1 = 7, but it says 21

7 # 1 = 21 breaks the rule → option (d).

Why the others are wrong

(a)
6 # 2 = 12 — 6 # 2 = 12 fits the product rule, 6 × 2 = 12. It is one of the three that agree.
(b)
5 # 3 = 15 — 5 # 3 = 15 fits: 5 × 3 = 15, the same rule that (a) and (c) follow.
(c)
4 # 4 = 16 — 4 # 4 = 16 fits: 4 × 4 = 16. Two equal numbers make it look different, but the product still holds.

Concept

In an odd-one-out built on a made-up symbol, the symbol hides one rule that three options obey. Find a rule that fits three and check it on the fourth.

Here the three results are exactly the products. 21 is 3 × 7, so 7 # 1 would need a different rule from the rest.

Make sure no other rule fits a different three. None does here: a rule such as 3 × a × b would give 7 # 1 = 21, but it makes 6 # 2 = 36, not 12.

Key facts

6 × 2 = 12, 5 × 3 = 15 and 4 × 4 = 16.
7 × 1 = 7, so 7 # 1 = 21 breaks the product rule.
An odd-one-out rule must hold for exactly three of the four options.

Study next

Symbol equations where a @ b stands for 2 × (a + b) or a² + b²Finding a missing result from two worked symbol examplesOdd-one-out number pairs built on squares and cubes

Common traps

Picking 4 # 4 = 16 because its two numbers are equal
Stopping at the first option that fits instead of testing all four

15 Sep 2025, 12:30, Reasoning Q.9 sets the same odd-one-out with @: three options obey a @ b = 2 × (a + b), and 7 @ 1 = 14 breaks it (keyed b).

Related PYQs

No directly related past PYQ was found.

Topic: Semantic Classification — all 59 SSC CGL questions on it, every solved shift.