Which of the following numbers is divisible by 7?

Correct option is C

Given:

Numbers: 894, 87, 875, 687.

Determine which is divisible by 7 .

Concept Used:
Divisibility rule for 7 (difference method):
Take the last digit, double it, and subtract from the remaining truncated number.

Repeat until small. If the result is a multiple of 7 (…, -14, -7, 0, 7, 14, …), the original number is divisible by 7.

Solution:

894 → (89 - 2$$\times4 = 81) → (8 - 2\times1$$​= 6) (not multiple of 7) not divisible.

87 → ($$8 - 2\times7 = -6)$$​ (not multiple of 7) not divisible.

875 → ($$87 - 2\times5 = 77)$$​(multiple of 7) divisible.

687 → $$(68 - 2\times7 = 54) → (5 - 2\times4 = -3$$​) (not multiple of 7)  not divisible.

Answer: 875 (Option C).

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