SSC CGL 2024 Tier-I · 13 September 2024, Shift 1 · General Intelligence and Reasoning · Question 6 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 10 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.) 3 : 25 4 : 62

(a)5 : 123
(b)6 : 218
(c)7 : 345
(d)9 : 731

Answer

Why

Correct — A. Rule: cube the first number, then subtract 2.

3³ = 27 and 27 − 2 = 25
4³ = 64 and 64 − 2 = 62

Two model pairs agreeing fixes the rule. Now apply it forward:
5³ = 125 and 125 − 2 = 123

That is the pair printed in option (a). The stem's note matters too — the cube is taken of 5 as a whole number, not of any digit of it.

Why the others are wrong

(b)
6 : 218 — 6 : 218 adds where the rule subtracts. 6³ = 216 and 216 + 2 = 218, while the model pairs both sit 2 below the cube.
(c)
7 : 345 — 7 : 345 repeats the same sign error: 343 + 2. Under the rule 7 would pair with 7³ − 2 = 341.
(d)
9 : 731 — 9 : 731 is 729 + 2. All three wrong pairs are n³ + 2, so this item turns entirely on the direction of the 2.

Concept

When the second number of a pair dwarfs the first, test a square, a cube or a near neighbour of one before anything else.

The habit that solves them fast: take the first number of a model pair, write n² and n³ beside it, then look two or three either side and see which value lands on the partner.

Here 3 goes to 25, which is 2 below 3³ = 27, and 4 goes to 62, which is 2 below 4³ = 64. Two pairs agreeing fixes a rule; one pair never does.

Then test the rule forward on each option rather than hunting for the option that feels closest.

The bracketed note forbids splitting a number into its digits. It rules out reading 13 as 1 and 3, which is the shortcut this family of question is designed to block.

Key facts

3³ = 27 and 27 − 2 = 25.
4³ = 64 and 64 − 2 = 62.
5³ = 125 and 125 − 2 = 123.
6³ = 216, 7³ = 343 and 9³ = 729 are the cubes behind the three wrong pairs.

Study next

Cubes to 15 and squares to 30 held in memoryPair rules shaped as n³ plus or minus a small constantConfirming a candidate rule on the second model pair before using it

Common traps

Fixing the rule from one model pair and never checking it against the second
Reading n³ + 2 for n³ − 2 once the numbers are large enough that the gap looks small

This stem gives two model pairs and asks for a third. Number-set relationships also appear in this shift at Reasoning Q.16, Q.20 and Q.21.

Related PYQs

No directly related past PYQ was found.