SSC CGL 2025 Tier-I · 15 September 2025, Shift 3 · General Intelligence and Reasoning · Question 19 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.

In each of the following questions, a group of three numbers/symbols is given in each option. Identify the group that does NOT follow the same pattern as the others.

(a)M13 : O15 : Q17
(b)N14 : P16 : R18
(c)L12 : N14 : P16
(d)O15 : Q17 : S21

Answer

Why

Correct — D.
Rule: each number is its letter's position, and the letters step +2.

M13 : O15 : Q17 → M = 13, O = 15, Q = 17.
N14 : P16 : R18 and L12 : N14 : P16 pair up the same way.

In O15 : Q17 : S21, S is the 19th letter, not the 21st → option (d).

Why the others are wrong

(a)
M13 : O15 : Q17 — M13 : O15 : Q17 pairs each letter with its true position and steps the letters by 2, the pattern the majority share.
(b)
N14 : P16 : R18 — N14 : P16 : R18 matches too: N is 14th, P 16th and R 18th, each letter two places after the last.
(c)
L12 : N14 : P16 — L12 : N14 : P16 fits the same rule: L 12, N 14, P 16, with the letters two apart.

Concept

A letter-number group hides its rule in two places: the pairing (is the number the letter's position, A = 1 to Z = 26, or a fixed distance from it?) and the step from one pair to the next.

Here the pairing is the plain position and the step is +2. S21 is the one pair of the twelve that breaks the pairing, since S = 19.

Checking the letters alone does not find it: O, Q, S still step by 2, like every other group here. The numbers give it away, jumping 15, 17, then 21.

Key facts

Positions to know: L 12, M 13, N 14, O 15, P 16, Q 17, R 18, S 19.
In each regular group here the letters and numbers both rise by 2.
S is the 19th letter, so S21 is off by 2.

Study next

Letter-number groups where the number is position + 1, as in A2, C4Groups whose letters step backward, such as K11 : I9 : G7Reverse alphabet positions: A = 26, Z = 1

Common traps

Checking only the letter step, which O, Q, S passes
Taking S as the 21st letter (21st is U)

Reasoning Q.20 of this shift adds symbols and sets each number one above its letter's position.

12 Sep 2025, 09:00, Reasoning Q.20 keeps every pair on its true position and hides the break in the step: N14 : K11 : H8 steps back by 3 where the rest step back by 2.

Related PYQs

No directly related past PYQ was found.

Topic: Symbolic/Number Classification — all 45 SSC CGL questions on it, every solved shift.