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Prime Factors question

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Prime Factors question

by zueswoods » Mon Apr 02, 2012 8:13 am
Hi

This is a question I encountered:

Is s divisible by 32?
(1) S is divisible by 16
(2) s is divisble by 4

My technique (learned from mgmat) is to simply find the primes and see if we do find 2^5 (without any overlaps).

32 = 2^5

(1) 16 = 2^4 not suff

(2) 4 = 2^2 not suff

Together, no new information is gained so insuff - because of overlap.

Offical Answer: E

HOWEVER what if statement 2 was "S is divisble by 24"

24 = (2^3)(3)

Would the answer still be E?
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by Bill@VeritasPrep » Mon Apr 02, 2012 8:31 am
Yes, it would. As you said, the prime factors are:

16=2^4
24=2^3 * 3

Which means the lowest common multiple is 2^4 * 3, or 48. 48 is not divisible by 32, but 96 is. This mean that we can't say definitively that S will or will not be divisible by 32.
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by zueswoods » Mon Apr 02, 2012 9:49 am
Sweet thanks!
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