SSC CGL 2024 Tier-I · 25 September 2024, Shift 3 · Quantitative Aptitude · Question 10 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.

The value of N in the equation 9 × N of 4 ÷ 4 − 15 × 4 = 12 is:

(a)0
(b)9
(c)8
(d)12

Answer

Why

Correct — C. The stem is an image, and it reads: the value of N in the equation 9 × N of 4 ÷ 4 − 15 × 4 = 12.

Under BODMAS the of is settled first:
9 × N of 4 = 9 × 4N = 36N
36N ÷ 4 = 9N
15 × 4 = 60

So 9N − 60 = 12
9N = 72
N = 8 → option (c).

Why the others are wrong

(a)
0 — Substitute N = 0 and the whole first term vanishes: 0 − 60 = −60, nowhere near 12. The 9N block has to reach 72 on its own, and zero cannot get there.
(b)
9 — 9 is the coefficient, not the unknown. Stopping at 9N = 72 and marking 9 gives a left side of 81 − 60 = 21, not 12 — the last step, dividing 72 by 9, is the answer.
(d)
12 — 12 is the right-hand side of the equation copied across. Substituted for N it gives 9 × 12 − 60 = 48, four times the target.

Concept

BODMAS fixes the order of operations, and the letter deciding this question is O, for 'of'. 'N of 4' means N × 4, and it is resolved before the division printed beside it.

Once 'of' is cleared the expression is linear: an unknown times a number, minus a constant, equal to a constant. Isolate the N-term, then divide.

On a single-unknown item the fastest safe move is to substitute each option back. Four quick evaluations beat one careful simplification you have no way of checking.

The question is printed as an image on the response sheet, so the expression itself — not the wording around it — carries the whole item.

Key facts

In BODMAS, 'of' is the O step and is resolved before division and multiplication.
9 × N of 4 ÷ 4 simplifies to 9N, because 36N ÷ 4 = 9N.
N = 8 satisfies the equation exactly: 9 × 8 of 4 ÷ 4 = 72, and 72 − 60 = 12.

Study next

Order of operations when 'of' sits next to a division signSolving one-step linear equations of the form aN − b = cChecking a numerical option by substituting it back into the stem

Common traps

Solving as far as 9N = 72 and then marking 9, the coefficient, instead of dividing to reach 8.
Adding 60 to the left side instead of subtracting, which turns 9N = 72 into 9N = −48.
Copying the right-hand side, 12, straight into the answer.

Set elsewhere as a plain 'Simplify the following expression' with 'of' buried among the ÷ signs — 13 Sep 2024, 09:00, Quant Q.15 and 26 Sep 2024, 12:30, Quant Q.19. This item inverts it: the value is given and the unknown sits inside the expression.

Related PYQs

No directly related past PYQ was found.