If A and B are positive integers, is the product AB even?

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swerve: Legendary Member; Posts: 2535; Joined: Sun Oct 29, 2017 2:04 pmFollowed by: 6 members

by swerve » Mon Apr 22, 2019 12:42 pm

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If A and B are positive integers, is the product Ab even?

1) The sum A + B is odd.
2) A is even.

The OA is D

Source: Official Guide

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Source: Beat The GMAT — Data Sufficiency | Mon Apr 22, 2019 12:42 pm

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Jay@ManhattanReview: GMAT Instructor; Posts: 3008; Joined: Mon Aug 22, 2016 6:19 amFollowed by: 34 members; Location: Grand Central / New York; Thanked: 470 times

by Jay@ManhattanReview » Tue Apr 23, 2019 12:50 am

swerve wrote:If A and B are positive integers, is the product AB even?

1) The sum A + B is odd.
2) A is even.

The OA is D

Source: Official Guide

For AB to be even, at least one between A and B must be even. AB would be odd only if both A and B are odd.

Let's take each statement one by one.

1) The sum A + B is odd.

Since A + B is odd, one between A and B is even and the other is odd. Thus, AB is even, Sufficient.

2) A is even.

Since A is even, we have at least one between A and B is even. Sufficient.

The correct answer: D

Hope this helps!

-Jay
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