SSC CGL 2024 Tier-I · 9 September 2024, Shift 3 · General Intelligence and Reasoning · Question 7 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.

Which two numbers (not digits) should be interchanged to make the given equation correct? 24 ÷ 3 – 4 × 2 + 6 × 5 +12 = 50

(a)4 and 3
(b)5 and 4
(c)3 and 2
(d)24 and 12

Answer

Why

Correct — D. First evaluate the equation exactly as printed.

24 ÷ 3 – 4 × 2 + 6 × 5 + 12
= 8 − 8 + 30 + 12 = 42, not 50. It is 8 short.

Now interchange 24 and 12:
12 ÷ 3 – 4 × 2 + 6 × 5 + 24

By BODMAS, division and multiplication first:
12 ÷ 3 = 4
4 × 2 = 8
6 × 5 = 30

Then left to right: 4 − 8 = −4, then −4 + 30 = 26, then 26 + 24 = 50.

The equation balances, so the pair to swap is option (d).

Why the others are wrong

(a)
4 and 3 — Swapping 4 and 3 gives 24 ÷ 4 – 3 × 2 + 6 × 5 + 12 = 6 − 6 + 30 + 12 = 42. The division loses 2 and the subtracted product loses 2, so the two changes cancel.
(b)
5 and 4 — Swapping 5 and 4 gives 24 ÷ 3 – 5 × 2 + 6 × 4 + 12 = 8 − 10 + 24 + 12 = 34. That moves the total the wrong way, away from 50 rather than towards it.
(c)
3 and 2 — Swapping 3 and 2 gives 24 ÷ 2 – 4 × 3 + 6 × 5 + 12 = 12 − 12 + 30 + 12 = 42. The division gains 4 and the subtracted product gains 4, so once again nothing changes.

Concept

Interchange questions are arithmetic, not inspection. Evaluate the equation as printed first: the shortfall tells you how large a change the swap has to produce.

Printed, this one gives 42 against a required 50 — a gap of +8.

Now think in terms of that gap. Swapping 24 and 12 turns 24 ÷ 3 = 8 into 12 ÷ 3 = 4, losing 4, and turns the trailing + 12 into + 24, gaining 12. Net change −4 + 12 = +8, exactly the gap.

BODMAS governs throughout: division and multiplication before addition and subtraction.

The stem says numbers, not digits. You interchange whole terms such as 24 and 12, never the figures inside them.

Key facts

As printed the equation equals 42, against a target of 50, so the swap must add 8.
Under BODMAS, division and multiplication are done first, then addition and subtraction run left to right.
Swapping 24 and 12 loses 4 at the division and gains 12 at the final term, a net gain of 8.

Study next

Interchange-the-signs questions, where two operators are swapped instead of two numbersBODMAS drills that pass through negative intermediate valuesJudging which swap can move a total far enough, before testing any option

Common traps

Trying the four options at random instead of first working out the gap of 8.
Adding before multiplying and so starting from the wrong printed total.
Swapping digits rather than whole numbers, which the stem's wording rules out.

SSC marks the stem 'numbers (not digits)' to close off digit swapping.

Evaluate the printed equation first. The size of the gap usually names the swap before a single option has been tested.

Related PYQs

No directly related past PYQ was found.