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official guide for gmat review, 11th edition, pg 327

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fonger
 Post subject: official guide for gmat review, 11th edition, pg 327
 Post Posted: Sun Apr 13, 2008 4:19 am 
the official guide for GMAT review, 11th Edition, page 327, answer to problem 118.

i think there's an error to the explanation, not the answer key.

the answer says "taking (1) and (2) together, n could only be 1,2,3, and 5, all of which will yield an integer in the expression 150/n."

stem 2 says n is a prime number, and 1 is not a prime number. n could only be 2,3, and 5, and the answer still holds true.

fonger
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RonPurewal
 Post subject: Re: official guide for gmat review, 11th edition, pg 327
 Post Posted: Wed Apr 16, 2008 4:44 am 
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ManhattanGMAT Staff


Posts: 7146
fonger wrote:
the official guide for GMAT review, 11th Edition, page 327, answer to problem 118.

i think there's an error to the explanation, not the answer key.

the answer says "taking (1) and (2) together, n could only be 1,2,3, and 5, all of which will yield an integer in the expression 150/n."

stem 2 says n is a prime number, and 1 is not a prime number. n could only be 2,3, and 5, and the answer still holds true.

fonger


you are correct; 1 is not prime.
be advised that OG answer keys are consistently of lower quality than the questions themselves. (although this situation is certainly less than ideal, it is also much better than vice versa.) apparently, gmac's best writers are too busy writing new problems to be able to write their own answer keys. :)

incidentally, the OG is a banned source, but, since you're not posting an actual question, i'll leave this thread up long enough to confer with the other moderators as to whether we can allow it to remain.
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