SSC CGL 2024 Tier-I · 24 September 2024, Shift 2 · General Intelligence and Reasoning · Question 5 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.

Which two signs should be interchanged to make the following equation correct? 29 × 145 + 5 − 640 ÷ 15 = 216

(a)− and ×
(b)÷ and +
(c)− and +
(d)÷ and ×

Answer

Why

Correct — B. Rewrite the equation under each proposed swap and evaluate by BODMAS.

Swap ÷ and +: 29 x 145 + 5 - 640 ÷ 15 becomes 29 x 145 ÷ 5 - 640 + 15.

29 x 145 = 4205
4205 ÷ 5 = 841
841 - 640 = 201
201 + 15 = 216

216 is the right-hand side the paper prints, so option (b) is the swap that repairs the equation.

Why the others are wrong

(a)
− and × — Swapping - and x gives 29 - 145 + 5 x 640 ÷ 15. Since 5 x 640 ÷ 15 is about 213.3, the left side lands near 97, nowhere near 216.
(c)
− and + — Swapping - and + gives 29 x 145 - 5 + 640 ÷ 15. The product 29 x 145 = 4205 survives untouched, so the total cannot fall to 216.
(d)
÷ and × — Swapping ÷ and x gives 29 ÷ 145 + 5 - 640 x 15. The term 640 x 15 = 9600 drags the left side deeply negative.

Concept

This family hands you a false equation and asks which single swap repairs it. There is no clever shortcut: substitute each option and evaluate, but evaluate under BODMAS rather than left to right.

What does speed you up is a size check. Before any arithmetic, ask what each swap does to the largest term.

A swap that leaves 29 x 145 = 4205 standing as a product, or that creates 640 x 15 = 9600, cannot reach a target of 216. That removes two options in seconds and leaves two worth computing.

The swap applies to every occurrence of both signs, not to the first one you meet. Changing one occurrence and leaving another is how a plausible but wrong total appears.

Key facts

Under BODMAS, x and ÷ rank equally and are worked left to right, so 29 x 145 ÷ 5 means (29 x 145) ÷ 5.
29 x 145 = 4205 and 4205 ÷ 5 = 841, the step that lets this equation land on 216.
A sign swap replaces every occurrence of both signs in the expression.

Study next

Sign-interchange equations where the target value is reached by a division early in the lineBODMAS on expressions mixing a multiplication and a division without bracketsEstimating the size of each term to eliminate options before computing

Common traps

Evaluating the rewritten line left to right and losing it at the first step.
Swapping the signs in the answer options rather than in the equation.
Stopping at 841 - 640 = 201 and reading 201 as near enough to 216.

The stem wording is fixed — which two signs should be interchanged to make the following equation correct — and it recurs at 10 Sep 2024, 09:00, Reasoning Q.16, at 12 Sep 2024, 09:00, Reasoning Q.19 and at 25 Sep 2024, 12:30, Reasoning Q.2.

Related PYQs

No directly related past PYQ was found.