SSC CGL 2025 Tier-I · 15 September 2025, Shift 2 · General Intelligence and Reasoning · Question 7 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.

What comes next: 1, 4, 27, 256, ?

(a)625
(b)2195
(c)312
(d)3125

Answer

Why

Correct — D.
Rule: each term is n raised to the power n.

1 = 1¹
4 = 2²
27 = 3³
256 = 4⁴

Next term: 5⁵ = 5⁴ × 5
= 625 × 5 = 3125 → option (d).

Why the others are wrong

(a)
625 — 625 is 5⁴. It raises the next base to the old exponent, but the rule raises both, so the next term is 5⁵, five times larger.
(b)
2195 — 2195 is not a power of 5 at all: it falls between 5⁴ = 625 and 5⁵ = 3125. No nⁿ value lands there.
(c)
312 — 312 is 3125 with its last digit dropped. 5⁵ must end in 5, as every power of 5 does.

Concept

The jumps are too big for squares (1, 4, 9, 16), so test the terms as powers with a rising exponent. 4 = 2², 27 = 3³ and 256 = 4⁴ show the base and the exponent rising together.

Write each term as nⁿ and the next is 5⁵. One quick check: every power of 5 ends in 5, which rules out 312 at a glance.

256 can also be written as 16² or 2⁸. Only 4⁴ continues the base-equals-exponent pattern set by 1¹, 2² and 3³.

Key facts

nⁿ for n = 1 to 5: 1, 4, 27, 256, 3125.
5⁴ = 625 and 5⁵ = 3125.
Every positive whole-number power of 5 ends in the digit 5.

Study next

Series of squares and cubes, such as n² or n³ − 1Series that alternate squares and cubesPerfect squares to 30² and cubes to 20³, for quick recognition

Common traps

Choosing 625 by raising 5 to the old exponent 4
Reading 256 as 16² and looking for a square series

14 Sep 2025, 09:00, Reasoning Q.18 fixes the exponent at 2: 1, 4, 9, 16, ?, 36 is keyed 25.

21 Sep 2025, 16:00, Reasoning Q.15 fixes it at 3 and subtracts 1: 0, 7, 26, 63, ? is keyed 124 = 5³ − 1.

Related PYQs

No directly related past PYQ was found.

Topic: Number Series — all 112 SSC CGL questions on it, every solved shift.