SSC CGL 2025 Tier-I · 18 September 2025, Shift 1 · General Intelligence and Reasoning · Question 1 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.

Select the letter-cluster from among the given options that can replace the question mark (?) in the following series. CFJ, FIM, ILP, ?

(a)LKN
(b)LOS
(c)NHS
(d)KIS

Answer

Why

Correct — B.
Rule: each position moves +3 from one cluster to the next.

First letters: C, F, I → L
Second letters: F, I, L → O
Third letters: J, M, P → S

Inside each cluster the steps are +3, +4 (C → F → J), and L → O → S keeps them.

LOS → option (b).

Why the others are wrong

(a)
LKN — LKN starts correctly with L, but the second letters run F, I, L, so the next is O. K and N also break the +3, +4 steps inside the cluster.
(c)
NHS — NHS ends in the right S, but the first letters run C, F, I, and I + 3 is L, not N.
(d)
KIS — KIS starts with K, just two steps after I. The first letters move +3 each time, so the cluster must start with L.

Concept

Read a letter-cluster series column by column. Each position forms its own series: the first letters run C, F, I, the second F, I, L and the third J, M, P, each climbing by 3.

There is a second check inside each cluster: C → F is +3 and F → J is +4, and every cluster repeats those steps. An answer that passes both checks is safe.

The second and third columns are the first column shifted: F, I, L is C, F, I moved +3, and J, M, P is C, F, I moved +7.

So once the first letter is L, the rest follow: L + 3 = O and L + 7 = S.

Key facts

C = 3, F = 6, I = 9, L = 12, O = 15 in alphabet positions.
J = 10, M = 13, P = 16, S = 19 in alphabet positions.
E = 5, J = 10, O = 15, T = 20, Y = 25 are quick reference points for counting positions.

Study next

Letter-cluster series where each position moves by a different stepLetter series that wrap past Z back to AClusters with a fixed gap pattern inside each cluster, such as +3, +4

Common traps

Checking only the first letter, when LKN also starts with L
Counting the gap from C to F as 2 (the letters D and E between them) instead of the step of 3

14 Sep 2025, 09:00, Reasoning Q.3 also moves every position +3: CDE, FGH, IJK, ?, keyed LMN, on the same C, F, I, L first letters.

14 Sep 2025, 09:00, Reasoning Q.5 adds a wrap: LWB, OZE, RCH, UFK, ?, keyed XIN, where Z + 3 runs round to C.

Related PYQs

No directly related past PYQ was found.

Topic: Semantic Series — all 125 SSC CGL questions on it, every solved shift.