SSC CGL 2025 Tier-I · 12 September 2025, Shift 2 · General Intelligence and Reasoning · Question 17 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 13 September 2026.

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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.

One number is not like the others: 1331, 2197, 3375, 4096

(a)1331
(b)3375
(c)4096
(d)2197

Answer

Why

Correct — C. Take the cube root of each number.

Rule: cubes of the odd numbers 11, 13, 15.

1331 = 11³
2197 = 13³
3375 = 15³
4096 = 16³, the cube of an even number.

Parity and squares agree: 4096 is the one even number of the four, and it is also 64², a perfect square. So 4096, option (c), is the odd one out.

Why the others are wrong

(a)
1331 — 1331 = 11³, an odd number cubed, like 13³ and 15³. It also reads the same backwards, but that is a surface feature; its cube root puts it in the group.
(b)
3375 — 3375 = 15³. 15 is odd, so 3375 sits in the odd-cube group with 1331 and 2197.
(d)
2197 — 2197 = 13³ (13 × 13 = 169, × 13 = 2197). It fills the gap between 11³ and 15³ in the odd-cube group.

Concept

Four-digit numbers in an odd-one-out can hide powers. If you know the cubes of 11 to 20 by sight, this becomes recognition, not calculation.

Here all four numbers are cubes, so 'is it a cube?' separates nothing. The next layer is the cube roots: 11, 13 and 15 are odd, 16 is even.

An odd-one-out can have more than one defensible rule, so the safe reading is the one where every rule agrees.

Here they do. 4096 is the only even number of the four, and it is the only perfect square, 64². Either route reaches option (c).

Key facts

11³ = 1331, 13³ = 2197, 15³ = 3375, 16³ = 4096.
4096 = 16³ = 64² = 2¹².
An odd number cubed is odd, and an even number cubed is even.

Study next

Cubes of 1 to 20 by sightNumbers that are both squares and cubes, such as 64 and 4096Series built on cubes, such as 11³, 22³, 33³, 44³

Common traps

Stopping at 'all four are cubes' and guessing, instead of comparing the cube roots.
Picking 1331 because it reads the same backwards, when the cube roots give a rule for all four.

Cubes also drive 17 Sep 2025, 16:00, Reasoning Q.9, where 1331, 10648, 35937, 85184 are 11³, 22³, 33³, 44³ and the next term is 55³ = 166375.

At 11 Sep 2024, 09:00, Reasoning Q.21, 8 → 512 and 12 → 1728 are cubes, so 15 → 3375, the same 15³ as here.

Related PYQs

No directly related past PYQ was found.

Topic: Symbolic/Number Classification — all 50 SSC CGL questions on it, every solved shift.