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Source: — Data Sufficiency |
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by ShadowN » Sat Jul 03, 2010 3:37 pm
The answer is B.


for xy to be a multiple of 105 (prime factorization of 5,3, 7), xy must have at least one 5, one 3 and one 7.

Only statement 2 tells us that y is a multiple of 5, the prime number we are looking for.

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by Patrick_GMATFix » Sat Jul 03, 2010 10:13 pm
Hi aznmexicana,

The key to this question, as to many DS questions, is accurate rephrasing. We know that xy is a multiple of 6*14, or of 2^2*3*7. We want to know whether xy is a multiple of 105, or of 3*5*7. Since we already know that xy is a multiple of 3*7, the rephrase is: "Is xy a multiple of 5?" Statement (2) gives us enough data to answer but statement (1) doesn't, so the answer is B

Attached is a more detailed solution and take-away strategies. If you cannot see the attachment, get it here

Good luck,
-Patrick
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by aznmexicana » Wed Jul 07, 2010 9:47 pm
thanks patrick!! that was really helpful!
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