SSC CGL 2025 Tier-I · 17 September 2025, Shift 1 · General Intelligence and Reasoning · Question 4 of 100

We transcribed this text from the pictures on a candidate's response sheet for this shift; the answer is the key SSC colour-marked on that sheet. Solution last reviewed 13 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. From 2025 the candidate response sheet prints every question and option as a picture, so the text here is transcribed from those pictures for this shift and checked against them independently; where the layout carries meaning, the picture is shown as well. Each answer is the key SSC colour-marked on that sheet. SSC released a tentative key for challenge and later its final one, both only to candidates behind a login, and the sheet does not say which of the two it carries. The solutions are written by UnlockIAS.

The following equation is incorrect. Which two signs should be interchanged to correct the equation? 18 + 6 × 4 − 12 ÷ 3 = 17

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

Answer

Why

Correct — D.
Rule: swap the two signs, then solve with BODMAS (× and ÷ before + and −).

Swap − and ÷: 18 + 6 × 4 ÷ 12 − 3
6 × 4 = 24, then 24 ÷ 12 = 2
18 + 2 = 20
20 − 3 = 17, the right-hand side → option (d).

Why the others are wrong

(a)
+ and × — Swapping + and × gives 18 × 6 + 4 − 12 ÷ 3 = 108 + 4 − 4 = 108, far from 17.
(b)
× and ÷ — Swapping × and ÷ gives 18 + 6 ÷ 4 − 12 × 3 = 18 + 1.5 − 36 = −16.5, not 17.
(c)
+ and − — Swapping + and − gives 18 − 6 × 4 + 12 ÷ 3 = 18 − 24 + 4 = −2, not 17.

Concept

In a sign-swap question the numbers stay where they are and two signs trade places. Rewrite the equation with the swap, then work it out in BODMAS order: × and ÷ from left to right first, then + and − from left to right.

As printed, the left side is 18 + 24 − 4 = 38, not 17, so a swap is needed.

A quick estimate narrows the search. The target, 17, is just below the first number, 18, so everything after 18 must come to −1. After the swap it does: + 2 − 3 = −1.

Key facts

BODMAS: × and ÷ first, left to right, then + and −.
As printed, the left side comes to 38.
Swapping − and ÷ gives 18 + 6 × 4 ÷ 12 − 3 = 17.

Study next

Sign swaps where two pairs of signs are interchanged at onceInterchanging two numbers (not digits) to balance an equationSymbol substitution with BODMAS, where symbols stand for + − × ÷

Common traps

Working strictly left to right without BODMAS, e.g. adding 18 + 6 before multiplying
Moving the numbers along with the signs, instead of keeping every number in place

19 Sep 2025, 09:00, Reasoning Q.8 asks the same: 97 × 23 − 18 + 9 ÷ 3 = 66 balances when × and + swap (keyed a).

17 Sep 2025, 12:30, Reasoning Q.5 balances 30 − 12 ÷ 3 × 2 + 4 = 122 by swapping − and × (keyed b).

Related PYQs

No directly related past PYQ was found.

Topic: Numerical Operations — all 148 SSC CGL questions on it, every solved shift.