SSC CGL 2024 Tier-I · 12 September 2024, Shift 1 · General Intelligence and Reasoning · Question 3 of 99

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.

Three of the following four options are alike in a certain way and thus form a group. Which is the one that does NOT belong to that group? (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/subtracting/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.)

(a)540 – 188 – 128
(b)81– 101– 92
(c)90 – 22– 12
(d)72 – 284 – 266

Answer

Why

Correct — D. Rule: first number = (second − third) × 9.

(a) 188 − 128 = 60, and 60 × 9 = 540 ✓
(b) 101 − 92 = 9, and 9 × 9 = 81 ✓
(c) 22 − 12 = 10, and 10 × 9 = 90 ✓

(d) 284 − 266 = 18, and 18 × 9 = 162, not the 72 that is printed.

Three rows obey the rule and one does not, so 72 – 284 – 266 is outside the group → option (d).

Why the others are wrong

(a)
540 – 188 – 128 — 540 = (188 − 128) × 9. The gap between the last two numbers is 60, and nine sixties is 540, so this row belongs to the group.
(b)
81– 101– 92 — 81 = (101 − 92) × 9. Here the second number is larger than the first, but the rule is about the gap between the last two, and that gap is 9.
(c)
90 – 22– 12 — 90 = (22 − 12) × 9. The gap is 10 and nine tens is 90, so the smallest triple in the set fits the rule exactly.

Concept

An odd-one-out on number triples is settled by finding one relation that three of the four rows satisfy exactly. Do not look for a story; look for an arithmetic link between the three numbers of a row.

The link here runs backwards along the row. Take the last two numbers, subtract, and multiply by 9 to reach the first.

Once a candidate rule fits two rows, test it on all four before answering. A rule that fits three and fails one is the answer; a rule that fits two is a coincidence.

The stem's NOTE forbids breaking a number into its digits, so 128 may not be read as 1, 2 and 8. That removes digit-sum and digit-reversal leads before you start.

Key facts

In rows (a), (b) and (c) the first number is nine times the gap between the second and the third.
For row (d) that product is 162, while the row prints 72.
The NOTE rules out digit-level operations, so every link must act on the whole number.

Study next

Odd-one-out on triples where the link is first times second equals thirdNumber analogies carrying the same whole-number NOTEThe nine times table up to 9 x 20, which makes this check instant

Common traps

Testing only the first-to-second gaps and giving up when they look random.
Splitting the numbers into digits, which the NOTE rules out.
Stopping at the first row that fits instead of confirming that exactly three fit.

Reasoning Q.5 of this shift carries the same whole-numbers NOTE, in slightly different words, and also asks for one arithmetic link that a whole row obeys, so the reading habit transfers directly.

Related PYQs

No directly related past PYQ was found.