SSC CGL 2024 Tier-I · 10 September 2024, Shift 2 · General Intelligence and Reasoning · Question 2 of 100

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 pair in which the numbers are related to each other in the same way as are the numbers in the given pairs. (NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g. 13 – Operations on 13 such as adding /deleting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.) 12 : 25 11 : 23

(a)15 : 29
(b)18 : 35
(c)25 : 49
(d)21 : 43

Answer

Why

Correct — D. Two sample pairs are given so that exactly one rule survives both.

12 → 25: 12 × 2 = 24, then + 1 = 25
11 → 23: 11 × 2 = 22, then + 1 = 23

Rule: second number = (first × 2) + 1.

Now test the options on their first numbers:

15 × 2 + 1 = 31
18 × 2 + 1 = 37
25 × 2 + 1 = 51
21 × 2 + 1 = 43 → option (d)

Why the others are wrong

(a)
15 : 29 — 15 × 2 + 1 = 31, not 29. This pair runs on (first × 2) − 1, which fits neither sample.
(b)
18 : 35 — 18 × 2 + 1 = 37. The printed 35 is 18 × 2 − 1, so the pair subtracts where the samples add.
(c)
25 : 49 — 25 × 2 + 1 = 51, not 49. Again 49 is 25 × 2 − 1, two short of the rule.

Concept

Number-pair analogies hand you two worked examples. One example can fit several rules, two rarely do, so test any candidate rule on both before touching the options.

The note in the stem matters as much as the numbers. It bars breaking 12 into 1 and 2, which removes digit sums, digit products and digit reversal from the search.

That leaves whole-number operations: add, subtract, multiply, divide, square, and combinations of two of them.

All three wrong options sit exactly two below the rule, because each uses (first × 2) − 1 instead of + 1. Spotting that shared near-miss is faster than testing four separate rules.

Key facts

The rule here is (first × 2) + 1, which turns 12 into 25 and 11 into 23.
The whole-number note forbids splitting 12 into 1 and 2.
Options (a), (b) and (c) each use (first × 2) − 1, landing two short.

Study next

Number analogies built on n², n² ± n and n³Pairs where the rule is division rather than multiplicationOdd-one-out sets in which three pairs share a rule and one does not

Common traps

Splitting the numbers into digits, which the stem rules out in as many words.
Committing to a rule from the first sample pair alone.
Picking the option whose numbers look closest, when all three wrong ones are exactly two short.

Whole-number relations recur across this shift's Reasoning section — a related-number item at Q.5, an odd-one-out at Q.7 and a three-number set at Q.12 (10 Sep 2024, 12:30). All four carry the same note against splitting digits.

Related PYQs

No directly related past PYQ was found.