SSC CGL 2024 Tier-I · 17 September 2024, Shift 1 · General Intelligence and Reasoning · Question 6 of 98

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)26 – 95 – 21
(b)22 – 67 – 22
(c)20 – 15 – 51
(d)16 – 45 – 21

Answer

Why

Correct — B. Work on the whole numbers, as the NOTE demands, and ask whether the first number is built out of the other two.

Rule: first = second divided by 5, plus third divided by 3.

(a) 95 / 5 = 19 and 21 / 3 = 7, and 19 + 7 = 26. Fits.
(c) 15 / 5 = 3 and 51 / 3 = 17, and 3 + 17 = 20. Fits.
(d) 45 / 5 = 9 and 21 / 3 = 7, and 9 + 7 = 16. Fits.

In the remaining set, 67 does not divide by 5 and 22 does not divide by 3, so the relation cannot even be started. Option (b) is the set that does not belong.

Why the others are wrong

(a)
26 – 95 – 21 — 95 / 5 + 21 / 3 = 19 + 7 = 26, its own first number. It obeys the relation, and the odd set is the one that breaks it.
(c)
20 – 15 – 51 — 15 / 5 + 51 / 3 = 3 + 17 = 20, its first number exactly. Its middle number being smaller than its last is a distraction, not the grouping.
(d)
16 – 45 – 21 — 45 / 5 + 21 / 3 = 9 + 7 = 16, again its first number. It shares the last number 21 with set (a), which is cosmetic — the divisions are what group them.

Concept

Three-number odd-one-out sets are rarely grouped on size, and rarely on the gap between neighbours. They are grouped on one relation binding all three numbers.

The productive question is whether the outer numbers can be reduced to the first, and divisibility is the fastest screen. The second numbers run 95, 67, 15, 45 and 67 alone fails to divide by 5. The third numbers run 21, 22, 51, 21 and 22 alone fails to divide by 3.

Both failures land on the same set, which usually answers the question before the arithmetic is finished.

The NOTE is a real constraint, not boilerplate.

You may add, subtract, multiply or divide the whole numbers, but you may not split 95 into 9 and 5 and work on the digits.

Key facts

In sets (a), (c) and (d) the first number equals the second divided by 5 plus the third divided by 3.
The second numbers 95, 15 and 45 are multiples of 5, while 67 is not.
The third numbers 21, 51 and 21 are multiples of 3, while 22 is not.

Study next

Odd-one-out sets where the first number is rebuilt from the other twoDivisibility screens for 3, 5 and 9 used to shortlist a relation quicklyTwo-number analogies of the form second = a times first, plus or minus b

Common traps

Testing only consecutive differences, which give 69 and minus 74 in set (a) and settle nothing.
Choosing (c) because its middle number, 15, is smaller than its last.
Breaking 95 into 9 and 5, which the NOTE forbids.

Three-number odd-one-out sets carrying the same whole-numbers NOTE are set at 10 Sep 2024, 16:00, Reasoning Q.1 and at 17 Sep 2024, 16:00, Reasoning Q.8.

Related PYQs

No directly related past PYQ was found.