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If k is an integer, is k even?

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Source: — Data Sufficiency |

Re: If k is an integer, is k even?

by Brent@GMATPrepNow » Fri May 29, 2020 8:50 am
BTGModeratorVI wrote:
Fri May 29, 2020 6:32 am
If k is an integer, is k even?

(1) k > 1
(2) k^2 is an even integer.

Answer: B
Source: GMAT prep
Given: k is an integer

Target question: k even?

Statement 1: k > 1
There are infinitely many values of k that satisfy statement 1. Here are two:
Case a: k = 2. In this case, the answer to the target question is YES, k is even
Case b: k = 3. In this case, the answer to the target question is NO, k is not even
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: k^2 is an even integer.
In other words, (k)(k) is even
Since k is an INTEGER, we know that k must be ODD or EVEN
Let's examine each case:
Case a: k is odd. In this case, we get: (ODD)(ODD) is even. This doesn't work.
So, it CANNOT be the case that k is odd.
Case b: k is even. In this case, we get: (EVEN)(EVEN) is even. This works.
So it must be the case that k is even
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: B

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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