SSC CGL 2025 Tier-I · 23 September 2025, Shift 1 · General Intelligence and Reasoning · Question 7 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.

Find the missing number: 17 : 4914 :: 19 : ?

(a)6860
(b)6861
(c)6859
(d)6875

Answer

Why

Correct — A.
Rule: second number = first number cubed + 1.

Check: 17² = 289
289 × 17 = 4913 = 17³
4913 + 1 = 4914 ✓

Apply: 19² = 361
361 × 19 = 6859 = 19³
6859 + 1 = 6860 → option (a).

Why the others are wrong

(b)
6861 — 6861 is 19³ + 2. The given pair adds exactly 1 to the cube: 4913 + 1 = 4914.
(c)
6859 — 6859 is 19³ itself, the step that drops the + 1. 17³ is 4913 while the pair gives 4914, so the cube alone does not fit.
(d)
6875 — 6875 is 16 more than 19³, and nothing in 17 : 4914 adds 16. Its last digit fails too: 19³ + 1 must end in 0.

Concept

A number analogy asks for the operation that turns the first number into the second. When the second number is far larger, try powers: 17² = 289 is much too small, while 17³ = 4913 is one short of 4914.

That 'one short' is the rule, n³ + 1. Knowing the cubes up to 20 lets you see it on sight instead of by trial.

The unit digit is a fast check. The unit digit of n³ depends only on the unit digit of n, so 19³ ends like 9³ = 729, in 9, and 19³ + 1 ends in 0. 6860 is the option that does.

Key facts

17³ = 4913, 18³ = 5832, 19³ = 6859.
The unit digit of n³ depends only on the unit digit of n.
20³ = 8000, so 19³ falls just below it.

Study next

Analogies built on n³ + n² or n² − 1Cubes and squares from 11 to 30Unit-digit checks for powers

Common traps

Stopping at 19³ = 6859 and dropping the + 1 the given pair adds
Testing squares only: 17² = 289 is nowhere near 4914

24 Sep 2025, 12:30, Reasoning Q.9 builds on the cube as well: 11 : 1452 is 11³ + 11², keyed 12³ + 12² = 1872.

Related PYQs

No directly related past PYQ was found.

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