SSC CGL 2024 Tier-I · 19 September 2024, Shift 1 · General Intelligence and Reasoning · Question 12 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.

Two sets of numbers are given below. In each set of numbers, certain mathematical operation(s) on the first number result(s) in the second number. Similarly, certain mathematical operation(s) on the second number result(s) in the third number and so on. Which of the given options follows the same set of operations as in the given sets? (NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into their constituent digits. E.g. 13 – Operations on 13 such as adding/subtracting/multiplying 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 – 14 – 8 – 17; 12 – 15 – 9 – 18

(a)5 – 8 – 3 – 10
(b)6 – 9 – 3 – 12
(c)3 – 6 – 2 – 8
(d)4 – 7 – 12 – 18

Answer

Why

Correct — B. Read the differences along each given set.

11 - 14 - 8 - 17: 14 = 11 + 3, 8 = 14 − 6, 17 = 8 + 9
12 - 15 - 9 - 18: 15 = 12 + 3, 9 = 15 − 6, 18 = 9 + 9

Rule: +3, then −6, then +9, applied to the whole number each time.

Test it on 6:
6 + 3 = 9
9 − 6 = 3
3 + 9 = 12

That is 6 - 9 - 3 - 12 -> option (b).

Why the others are wrong

(a)
5 – 8 – 3 – 10 — 5 - 8 - 3 - 10 passes the first step, 5 + 3 = 8, but then needs 8 − 6 = 3, and 8 − 6 is 2. Its own steps are +3, −5, +7.
(c)
3 – 6 – 2 – 8 — 3 - 6 - 2 - 8 also opens with +3, but 6 − 6 = 0, not 2. Its steps are +3, −4, +6, so the fall is too shallow.
(d)
4 – 7 – 12 – 18 — 4 - 7 - 12 - 18 opens with +3 and then rises to 12 where the rule falls by 6. Its steps are +3, +5, +6.

Concept

A number-chain analogy asks for a fixed sequence of operations applied in the same order to every set. Find the differences first — here they are enough.

The differences are +3, −6, +9: a rise, then a fall, then a rise, each three larger than the last.

Test every step of a candidate, not the first one. A chain is only right if all three steps match, and options are built so that the early steps agree.

All four options open with +3, so the first step separates nothing. The second step, the fall of 6, is what decides the item.

Key facts

The operation chain is +3, then −6, then +9.
Both given sets obey it: 11 - 14 - 8 - 17 and 12 - 15 - 9 - 18.
The stem's note bars breaking a number into its digits before operating on it.

Study next

Number-chain analogies with a fixed sequence of operationsChains built on ×, ÷ or squares rather than on + and −Checking every step of a chain before committing to an option

Common traps

Stopping after the first step, which every option here passes.
Reading the differences correctly but applying them in the wrong order.
Splitting a two-digit number into its digits, which the stem's note forbids.

The note about operating on whole numbers is printed in the stem itself, so digit-level tricks are off the table — operate on 11, never on 1 and 1.

A different kind of number pattern sits at Reasoning Q.7 in this shift (19 Sep 2024, 09:00), where the operators themselves are interchanged.

Related PYQs

No directly related past PYQ was found.

Two sets of numbers are given below. In each set of numbers, certain mathematical operation(s) on the first number result(s) in the second number. Similarly, certain mathematical operation(s) on the second number result(s) in the third number and so on. Which of the given options follows the same set of operations as in the given sets? (NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into their constituent digits. E.g. 13 – Operations on 13 such as adding/subtracting/multiplying 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 – 14 – 8 – 17; 12 – 15 – 9 – 18

(a)5 – 8 – 3 – 10
(b)6 – 9 – 3 – 12
(c)3 – 6 – 2 – 8
(d)4 – 7 – 12 – 18