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If x and y are positive integers and y ≠ 1, then xy(y −1) is

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Bunuel
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If x and y are positive integers and y ≠ 1, then xy(y −1) is [#permalink] New post   17 Aug 2016, 01:56
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If x and y are positive integers and y ≠ 1, then xy(y −1) is

A. Always even
B. Always odd
C. Odd only when x is odd
D. Even only when y is even
E. Odd only when xy is odd
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A
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msk0657
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If x and y are positive integers and y ≠ 1, then xy(y −1) is [#permalink] New post   17 Aug 2016, 02:27
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Bunuel wrote:
If x and y are positive integers and y ≠ 1, then xy(y −1) is

A. Always even
B. Always odd
C. Odd only when x is odd
D. Even only when y is even
E. Odd only when xy is odd


Here given condition is x and y are positive integers and y ≠ 1, then xy(y −1) ?

As per the table result we always get even result..option A.
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Donnie84
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Re: If x and y are positive integers and y ≠ 1, then xy(y −1) is [#permalink] New post   18 Aug 2016, 17:13
Expression is xy(y-1). We can ignore x and only work with y.

If y = even -> entire expression is even since anything multiplied by even is even
If y = odd, y-1 -> even -> entire expression is even since anything multiplied by even is even

Hence, entire expression will always be even.

Answer (A).
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Re: If x and y are positive integers and y ≠ 1, then xy(y −1) is [#permalink] New post   20 Aug 2016, 05:06
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Bunuel wrote:
If x and y are positive integers and y ≠ 1, then xy(y −1) is

A. Always even
B. Always odd
C. Odd only when x is odd
D. Even only when y is even
E. Odd only when xy is odd


No need to do anything. It is given that y is positive integer > 1.

This implies y(y −1) is the product of 2 consecutive integers. Hence, product of 2 consecutive integers is always even and since x is also a positive integer, the answer should always be even.

hence, A
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Re: If x and y are positive integers and y ≠ 1, then xy(y −1) is [#permalink] New post   06 Dec 2020, 02:34
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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Re: If x and y are positive integers and y ≠ 1, then xy(y −1) is [#permalink]
06 Dec 2020, 02:34
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