SSC CGL 2024 Tier-I · 24 September 2024, Shift 2 · General Intelligence and Reasoning · Question 9 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 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.) 11 : 1331 9 : 729

(a)8 : 6561
(b)6 : 180
(c)7 : 343
(d)13 : 2028

Answer

Why

Correct — C. Rule: the second number is the cube of the first.

11 : 1331, and 11 x 11 x 11 = 1331.
9 : 729, and 9 x 9 x 9 = 729.

Test the options against n cubed: 7 x 7 x 7 = 343, which is option (c).

The printed note forbids splitting a number into its digits, so 1331 has to be reached from 11 taken whole — and cubing is what reaches it.

Why the others are wrong

(a)
8 : 6561 — 8 cubed is 512, not 6561. The number 6561 is 3 to the eighth power and is not the cube of any whole number.
(b)
6 : 180 — 6 cubed is 216. 180 is 6 x 30, and no rule that fits both 11 : 1331 and 9 : 729 produces it.
(d)
13 : 2028 — 13 cubed is 2197, not 2028. The gap is exactly 169, which is why 2028 looks close enough to pass a quick glance.

Concept

A number analogy asks for one operation that turns the left number into the right one, and the printed note narrows the search hard: you may add, subtract, multiply or take a power of the whole number, but you may not touch its digits.

Two pairs are given rather than one so that the rule is pinned down. 11 to 1331 on its own would also fit 11 x 121, but 9 to 729 kills that and leaves n to n cubed.

Cubes up to 15 are worth knowing on sight, because with them this item is a single look rather than a calculation.

The digit-splitting note is boilerplate SSC attaches to number-analogy items. It fences the method rather than hinting at the answer, so do not read anything into its presence.

Key facts

Cubes worth knowing on sight: 7 cubed is 343, 8 cubed is 512, 9 cubed is 729, 11 cubed is 1331, 12 cubed is 1728, 13 cubed is 2197.
6561 is 3 to the eighth power and lies between 18 cubed (5832) and 19 cubed (6859), so it is not a cube.
The note bars digit-level operations, so any valid rule must act on the number as a whole.

Study next

Number analogies built on squares, cubes and forms such as n cubed plus nCube roots, which are the same item run backwardsThree-term sets of the shape (n, n squared, n cubed), asked as set analogies

Common traps

Splitting 1331 into 1, 3, 3 and 1 even though the note forbids it.
Testing only the first pair, which 11 x 121 also satisfies.
Reading 2028 as 13 cubed because it starts near 2000.

The cube rule runs forwards at 11 Sep 2024, 09:00, Reasoning Q.21 (8 : 512, 12 : 1728, 15 : ?) and backwards at 24 Sep 2024, 16:00, Reasoning Q.3 (64 : 4, 216 : 6, 729 : ?). It also appears as the third term of a set at 23 Sep 2024, 12:30, Reasoning Q.18, where (3, 9, 27) and (4, 16, 64) lead to (7, 49, 343).

Related PYQs

No directly related past PYQ was found.