GMAT Test 2_DS Even Odd #28

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GMAT Test 2_DS Even Odd #28

by kwah » Tue Apr 03, 2012 7:14 pm
Attached is a question from GMAT Prep Test 2.

Please advise how to achieve the result.

Answer: A

Thanks,
K
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by Bill@VeritasPrep » Tue Apr 03, 2012 8:16 pm
S1) If 10 of the 20 terms are even, the remaining 10 must be odd.

S2) If 10 of the 20 terms are multiples of 4, then the remaining 10 must be odd or evens that aren't divisible by 4 (like 6 and 10). We could have anywhere from 0 to 10 odds. Insufficient.
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by Anurag@Gurome » Tue Apr 03, 2012 9:00 pm
kwah wrote:Attached is a question from GMAT Prep Test 2.

Please advise how to achieve the result.

Answer: A

Thanks,
K
Set S consists of 20 different positive integers. How many of the integers in S are odd?

1) 10 of the integers in S are even implies that exactly 10 integers are even and the remaining 10 integers are odd; SUFFICIENT.

2) 10 of the integers in S are multiples of 4 implies there could be some integers that are even but not multiples of 4 like, 6, 10 etc. In this case the number of odd integers may vary; NOT sufficient.

The correct answer is A.
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by kwah » Wed Apr 04, 2012 8:40 am
If we were to change the statement in 2) to...

2) 10 of the integers in S are multiples of 2

Then we could conclude that this is sufficient, correct?

Because this implies that there are only 10 even integers in set S. Therefore, answer would be D in this case (both sufficient).

Please confirm, thanks.

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by Bill@VeritasPrep » Wed Apr 04, 2012 8:47 am
kwah wrote:If we were to change the statement in 2) to...

2) 10 of the integers in S are multiples of 2

Then we could conclude that this is sufficient, correct?

Because this implies that there are only 10 even integers in set S. Therefore, answer would be D in this case (both sufficient).

Please confirm, thanks.
Yep. It would give us the same information that Statement 1 did, so it would also be sufficient and we would choose D.
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