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Question

The smallest four-digit number that is exactly divisible by each of 24, 40, and 56 is:

This question was previously asked in
RRB NTPC 2024 Undergraduate CBT 1 Question Paper (29-Aug-2025) (Shift 1)
The correct answer is

1680

The correct answer is option 3 i.e. 1680.

Step 1 – LCM: \(24 = 2^3 \times 3,\ 40 = 2^3 \times 5,\ 56 = 2^3 \times 7\). LCM \(= 2^3 \times 3 \times 5 \times 7 = 840\).

Step 2 – Smallest 4-digit multiple of 840: \(840 \times 2 = 1680\).

Hence option (3).

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