SSC CGL 2024 Tier-I · 11 September 2024, Shift 3 · General Intelligence and Reasoning · Question 11 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 option in which the numbers share the same relationship as that shared by the given pair of numbers. (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.) 17 : 253 19 : 271

(a)21 : 289
(b)23 : 207
(c)32 : 387
(d)31 : 400

Answer

Why

Correct — A.

Rule: the second number is nine times the first, plus 100.

9 times 17 is 153, and 153 plus 100 is 253
9 times 19 is 171, and 171 plus 100 is 271

Apply it to 21: 9 times 21 is 189, and 189 plus 100 is 289, which is option (a).

The multiplier is found from the gaps. The first numbers differ by 2 and the second numbers differ by 18, so each unit of the first is worth 9 in the second.

Why the others are wrong

(b)
23 : 207 — 207 is exactly 9 times 23 with the 100 left off. The multiplier is right and the constant is missing, so the pair fails.
(c)
32 : 387 — The rule gives 9 times 32 plus 100, which is 388. At 387 the pair falls one short, close enough to tempt and still wrong.
(d)
31 : 400 — 9 times 31 plus 100 is 379, not 400. The second number is 21 too large for the rule the sample pairs set.

Concept

When two pairs are given, treat them as two data points and fit the linear rule before trying anything cleverer.

The first numbers differ by 2 while the second numbers differ by 18, so the multiplier is 9. Then the constant: 253 minus 9 times 17 leaves 100, and the second pair agrees.

Squares and cubes are the usual alternative reading, but 253 and 271 are neither, so the linear rule is the one to carry to the options.

289 happens to be 17 squared, and 17 is the first number of the sample pair. That coincidence can send you hunting for a squaring rule that neither 253 nor 271 supports.

Key facts

The rule joining the pairs is second = 9 times first, plus 100.
Two pairs fix a linear rule: the ratio of the differences gives the multiplier.
9 times 21 plus 100 is 289, which is also 17 squared, so spotting a square does not by itself prove a pair.

Study next

Number pairs built on squares and cubes and their neighbours, such as n squared plus nFitting a rule from two data points, which is the algebra of a straight lineThree-number set items, where the same differencing method applies

Common traps

Testing each option against the first pair only, which lets 23 : 207 through
Hunting for a rule inside a single pair, such as a digit sum, when two pairs are given
Stopping at 387 for 32, which is one less than the rule requires

The pairs come with the note about not breaking numbers into digits, which points to a whole-number operation.

The same two-pair format is set at Reasoning Q.8 of the 11 Sep 2024, 12:30 shift, where the rule is a constant subtraction, and at Reasoning Q.15 of the 13 Sep 2024, 16:00 shift, where it is a straight multiple.

Related PYQs

No directly related past PYQ was found.