SSC CGL 2025 Tier-I · 23 September 2025, Shift 3 · General Intelligence and Reasoning · Question 10 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.

What comes next? 2, 4, 3, 6, 4, 8, ?

(a)5
(b)6
(c)9
(d)10

Answer

Why

Correct — A.
Rule: two series woven together: odd places +1, even places +2.

Odd places (1st, 3rd, 5th): 2, 3, 4
Even places (2nd, 4th, 6th): 4, 6, 8

The blank is the 7th term, an odd place, so it continues 2, 3, 4: 5 → option (a).

Read as pairs, the series is n, 2n: (2, 4), (3, 6), (4, 8), then (5, 10).

Why the others are wrong

(b)
6 — 6 repeats the previous drop of 2 (6 → 4). The drops grow, 4 → 3 is −1 and 6 → 4 is −2, so the next is −3: 8 − 3 = 5.
(c)
9 — 9 adds 1 to the last term, 8. The +1 steps belong to the odd-place terms 2, 3, 4, and 8 sits in the even-place series.
(d)
10 — 10 continues the even-place series 4, 6, 8, but that is the 8th term. The blank is the 7th, one place earlier.

Concept

A series that rises and falls in turn may be two series woven together. Split it by position and read each strand on its own.

Here the odd places count up by 1 and the even places by 2, which is the same as saying each even term is double the term before it. Once you know which strand the blank belongs to, the answer is one step away.

The series also reads as alternating operations: ×2, −1, ×2, −2, ×2, −3. That reading gives 8 − 3 = 5 as well, a useful cross-check.

Key facts

Odd places: 2, 3, 4, 5, rising by 1.
Even places: 4, 6, 8, rising by 2.
Each even-place term is twice the term before it.

Study next

Woven series where one strand multiplies and the other addsLetter series split into odd and even positionsSeries with alternating operations such as ×2 then −1

Common traps

Continuing the even-place strand and answering 10 for the 7th term
Repeating the previous drop of 2 and answering 6

Here the blank falls on an odd place, so the slower strand decides it.

12 Sep 2025, 09:00, Reasoning Q.8 weaves two +4 strands, 3, 12, 7, 16, 11, 20, 15, ?, and keys 24 from the even places. 18 Sep 2024, 12:30, Reasoning Q.14 weaves a +5 strand with a +10 strand and keys 35.

Related PYQs

No directly related past PYQ was found.

Topic: Number Series — all 178 SSC CGL questions on it, every solved shift.