SSC CGL 2025 Tier-I · 12 September 2025, Shift 3 · General Intelligence and Reasoning · Question 23 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 11 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.

If a % b = 37, where a % b = a + 2b, what is the value of a and b?

(a)25,5
(b)27, 5
(c)16, 10
(d)27, 10

Answer

Why

Correct — B. Rule: a % b means a + 2b, so the pair must satisfy a + 2b = 37.

Test a = 27, b = 5:
2b = 2 × 5 = 10
a + 2b = 27 + 10 = 37 ✓

The pair 27, 5 is option (b).

Why the others are wrong

(a)
25,5 — 25 + 2 × 5 = 25 + 10 = 35, which is 2 short of 37. With b = 5, a must be 37 − 10 = 27.
(c)
16, 10 — 16 + 2 × 10 = 16 + 20 = 36, which is 1 short of 37. With b = 10, a would have to be 17.
(d)
27, 10 — 27 + 2 × 10 = 27 + 20 = 47, not 37. With a = 27, 2b must be 10, so b is 5, not 10.

Concept

A defined operator is a formula in disguise. Replace a % b with a + 2b and the question becomes one equation: a + 2b = 37.

One equation in two unknowns cannot be solved outright, so the options do the work: substitute each pair and keep the one that gives 37.

Double b before adding. The 2 belongs to b alone, not to a or to the sum.

The question asks for "the value of a and b", but a + 2b = 37 alone allows many pairs, such as 35 and 1 or 17 and 10. The four options are what make the answer unique.

Key facts

By the question's definition, a % b = a + 2b.
27 + 2 × 5 = 37.
One linear equation in two unknowns has many solutions, so the options decide.

Study next

Operators defined by a formula, such as a * b = a² − bTwo equations in two unknowns solved by eliminationChecking options by substitution when an equation cannot be solved outright

Common traps

Adding b instead of 2b, which makes option (d) look right: 27 + 10 = 37.
Trying to solve a + 2b = 37 outright instead of testing the four pairs.

12 Sep 2025, 16:00, Reasoning Q.15 sets the same x + 2y shape with a second equation beside it, x − y = 5, and that second equation is what fixes one pair (x = 8, y = 3).

Related PYQs

No directly related past PYQ was found.

Topic: Numerical Operations — all 92 SSC CGL questions on it, every solved shift.