SSC CGL 2025 Tier-I · 24 September 2025, Shift 2 · General Intelligence and Reasoning · Question 6 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.

If 4#2=10 5#3=18 6#4=28 Then what is 7#5=?

(a)50
(b)60
(c)40
(d)70

Answer

Why

Correct — C.
Rule: a # b = (a + 1) × b.

4 # 2 = 5 × 2 = 10 ✓
5 # 3 = 6 × 3 = 18 ✓
6 # 4 = 7 × 4 = 28 ✓

7 # 5 = 8 × 5 = 40 → option (c).

Why the others are wrong

(a)
50 — 50 would be a rise of 22 from 28. The results 10, 18, 28 rise by 8 and then 10, so the next rise is 12, giving 40.
(b)
60 — 60 would be a rise of 32 from 28. The rule gives (7 + 1) × 5 = 40, a rise of 12 that continues 8, 10.
(d)
70 — 70 would be a rise of 42 from 28, where the rises so far are 8 and 10. The rule gives 8 × 5 = 40.

Concept

With three worked lines, watch how both inputs move. Here a runs 4, 5, 6 and b runs 2, 3, 4, and the results grow faster than either, so try a product first.

a × b gives 8, 15, 24. Each is short by exactly b (2, 3, 4), so the rule is a × b + b, which is (a + 1) × b.

A second route reaches the same answer. The results 10, 18, 28 rise by 8 and then 10, so the next rise is 12: 28 + 12 = 40.

Key facts

4 # 2 = 5 × 2, 5 # 3 = 6 × 3, 6 # 4 = 7 × 4.
7 # 5 = 8 × 5 = 40.
a × b + b and (a + 1) × b are the same rule.

Study next

Symbol rules such as a × b + a or a² − bNumber series whose differences grow by a fixed step

Common traps

Fitting a rule to the first line alone, such as a² − 3b (16 − 6 = 10), which gives 16 for 5 # 3, not 18
Reusing the addition meaning # has in Reasoning Q.5 of this paper

Here SSC gives three worked lines, enough to confirm a two-step rule.

Reasoning Q.5 of this paper uses # for plain addition (4 # 3 = 7), and 17 Sep 2025, 16:00, Reasoning Q.21 uses it for a rule that fits a² + b² − 3, keyed 58.

Related PYQs

No directly related past PYQ was found.

Topic: Symbolic/Number Analogy — all 210 SSC CGL questions on it, every solved shift.