SSC CGL 2024 Tier-I · 19 September 2024, Shift 3 · General Intelligence and Reasoning · Question 8 of 99

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 6 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

Select the number from the given options to complete the series. 58, 70, 83, 97, ___

(a)112
(b)113
(c)114
(d)111

Answer

Why

Correct — A.

Rule: the differences themselves climb by one — +12, +13, +14, +15.

58 → 70 is +12
70 → 83 is +13
83 → 97 is +14

The next difference must therefore be +15.
97 + 15 = 112, which is option (a).

Why the others are wrong

(b)
113 — 113 needs a jump of +16, skipping +15 altogether. The differences here rise by exactly one each time, so no step can be missed out.
(c)
114 — 114 needs a jump of +17. Nothing in the differences 12, 13, 14 leads to 17, and the series never doubles its increment.
(d)
111 — 111 needs +14 again, repeating the previous difference instead of raising it. That is the value you reach by treating the gaps as constant after 83.

Concept

When a number series shows no obvious multiplier, take first differences by subtracting each term from the next. If those are not constant, difference them again.

Here the first differences are 12, 13 and 14: not constant, but rising by 1. That second-level constant is what fixes the next term.

A series whose second differences are constant is generated by a quadratic expression in the position number, which is why the gaps grow steadily instead of doubling. Recognising the shape stops you hunting for a multiplication rule that is not there.

All four options lie within three of one another, so a single arithmetic slip still lands on a printed choice. Recompute rather than recognise.

Key facts

The first differences of 58, 70, 83 and 97 are 12, 13 and 14.
Those differences rise by 1, so the next is 15 and the next term is 112.
A series with constant second differences is quadratic in the position number.

Study next

Series whose second differences also rise, giving a cubic shapeAlternating series where two interleaved patterns share a single line of numbersSeries mixing operations, such as doubling and then adding three

Common traps

Repeating the last difference of +14 and answering 111.
Checking only 58 to 70 and 70 to 83, then assuming the increment without verifying the third gap.

A four-term additive series with close-packed options: the work sits in the second-level pattern, not in the addition.

Related PYQs

No directly related past PYQ was found.