SSC CGL 2025 Tier-I · 23 September 2025, Shift 3 · General Intelligence and Reasoning · Question 4 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.

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 should come in place of the question mark '?' in the following number series? 9, 14, 24, 39, 59, ?, 114

(a)69
(b)70
(c)89
(d)84

Answer

Why

Correct — D.
Rule: differences grow by 5 — +5, +10, +15, +20, +25, +30.

9 + 5 = 14
14 + 10 = 24
24 + 15 = 39
39 + 20 = 59

59 + 25 = 84
Check: 84 + 30 = 114, the printed last term → option (d).

Why the others are wrong

(a)
69 — 69 is 59 + 10, an early gap reused. It also fails the check at the end: 114 − 69 = 45, not the +30 the ladder needs.
(b)
70 — 70 is 59 + 11, leaving a jump of 44 to 114. Neither gap belongs to the +5, +10, +15 … ladder.
(c)
89 — 89 is 59 + 30, which skips the +25 step. The last gap would then be 114 − 89 = 25, so the ladder runs backwards.

Concept

When a series speeds up, write its first differences. Here they are 5, 10, 15, 20, 25 — the multiples of 5 — so each gap is 5 more than the one before.

The last term, 114, is printed after the blank. Use it: the blank must be 59 + 25 and must also leave a gap of 30 to 114. 84 passes both tests.

Key facts

First differences: 5, 10, 15, 20, 25, 30.
Second differences are constant at 5.
A term printed after the blank lets you check the answer from both sides.

Study next

Series whose differences are squares or cubesSeries whose differences double at each stepSeries that alternate two operations

Common traps

Accepting a value that fits the gap before the blank without testing the gap after it
Jumping to +30 after 59 and choosing 89

Here the differences are multiples of 5 and the blank sits one place before the end.

25 Sep 2024, 09:00, Reasoning Q.15 uses multiples of 11 the same way, 35, 46, 68, 101, 145, ? with gaps 11, 22, 33, 44, 55, and keys 200.

Related PYQs

No directly related past PYQ was found.

Topic: Number Series — all 178 SSC CGL questions on it, every solved shift.