SSC CGL 2024 Tier-I · 19 September 2024, Shift 3 · Quantitative Aptitude · Question 14 of 99

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 6 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

Which of the following numbers is NOT divisible by 8?

(a)5544
(b)7344
(c)7497
(d)4608

Answer

Why

Correct — C. 7497 is odd, so it is not divisible by 2, let alone by 8. That settles the question at a glance.

The formal test is the last three digits: a number is divisible by 8 exactly when the number they form is.

7497 → 497, and 497 = 8 × 62 + 1, remainder 1 → option (c)

The rest all pass: 5544 = 8 × 693, 7344 = 8 × 918, 4608 = 8 × 576.

Why the others are wrong

(a)
5544 — 5544 is divisible by 8. Its last three digits give 544 = 8 × 68, and the whole number is 8 × 693.
(b)
7344 — 7344 is divisible by 8. Its last three digits give 344 = 8 × 43, and the whole number is 8 × 918.
(d)
4608 — 4608 is divisible by 8, and comfortably so. 608 = 8 × 76, and 4608 = 2⁹ × 9, which makes it a multiple of 512.

Concept

Divisibility by 8 depends only on the last three digits, and the reason is worth knowing: 1000 = 8 × 125. Every digit above the hundreds place carries a multiple of 1000, so it is already a multiple of 8 and cannot affect the remainder.

That gives the working rule: a number is divisible by 8 when its last three digits form a multiple of 8. The same argument gives divisibility by 4 from the last two digits and by 2 from the last one.

On a NOT-divisible stem, screen for parity first. An odd number is never divisible by 8, and that alone disposes of 7497 without any three-digit arithmetic.

The stem asks which number is NOT divisible, so three options will divide cleanly and the fourth is the answer. Read the negation before you start testing anything.

Key facts

A number is divisible by 8 when the number formed by its last three digits is divisible by 8.
The rule holds because 1000 = 8 × 125, so every place above the hundreds contributes a multiple of 8.
497 leaves remainder 1 on division by 8, which is why 7497 fails.
5544 = 8 × 693, 7344 = 8 × 918 and 4608 = 8 × 576.

Study next

Divisibility rules for 4, 8 and 16 from the last two, three and four digitsFinding the missing digit that makes a number divisible by 8Divisibility by 11 from the alternating sum of digits

Common traps

Testing all four options in full when an odd number can be discarded on sight.
Using the last two digits instead of the last three, which wrongly rejects 5544 on 44.
Missing the NOT in the stem and marking a number that is divisible by 8.

Divisibility is asked both ways round: pick the odd one out, as here, or supply the digit that makes a number divide.

The digit-supplying version is asked at 12 Sep 2024, 16:00, Quant Q.10, where a value must be found for a in 91876a2 so that the number is a multiple of 8.

Related PYQs

No directly related past PYQ was found.