If a, b, c are integers and a = b - c , which of the following must be

Question

If a, b, c are integers and a = b - c , which of the following must be true ?

A) a is even
B) ab is even
C) ac is odd
D) abc is odd
E) abc is even

Bunuel · Answer

All three of the unknowns cannot be odd because odd - odd is even, not odd. So, at least one must be even, which makes abc even.

Answer: E.

Kinshook · Answer

Given: 
1. a, b, c are integers 
2. a = b - c

Asked: Which of the following must be true ?

b = a + c
If a & c are odd => b is even => abc is even
If a is even & c is odd => b is odd => abc is even
If a is odd & c is even = > b is odd => abc is even
If a & c is even => b is even => abc is even

In all cases
abc is even

IMO E

Harsh9676 · Answer

Good question.

I took the sample as

a= -2 b=0 and C= 2 first case

a=-3 b= 0 and c = 3. Sec case.

So abc will always be even.

Posted from my mobile device

bumpbot · Answer

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If a, b, c are integers and a = b - c , which of the following must be

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If a, b, c are integers and a = b - c , which of the following must be

Prep Toolkit

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