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Is xy a multiple of 105?

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Source: — Data Sufficiency |
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by aj5105 » Fri May 08, 2009 9:22 am
(1)

(18 * 210)/105 [Yes]

(18 * 14)/105 [No]

(2)

(6 * 525 * 14)/14 [Yes]

(6* 25* 14)/105*14 [No]


(1) + (2)

(E)


P.S : Can be done with much easier numbers.

OA?
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by crackgmat007 » Fri May 08, 2009 9:48 am
Even I got E...but the answer seems to be B (may be there is an error). Is anyone else geting E?
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Re: Is xy a multiple of 105?

by Ian Stewart » Fri May 08, 2009 3:04 pm
crackgmat007 wrote:If positive integer x is a multiple of 6 and positive integer y is a multiple of 14, is xy a multiple of
105?
(1) x is a multiple of 9.
(2) y is a multiple of 25.
If x is a multiple of 6, then x is a multiple of 2 and 3. If y is a multiple of 14, then y is a multiple of 2 and 7. So before looking at the statements, we know that xy is a multiple of 2^2 * 3 * 7. We want to know if xy is a multiple of 105 = 3*5*7. We already know that xy is a multiple of 3*7, so we only need to know if xy is a multiple of 5 to have sufficient information. S1 doesn't tell us that, but S2 does, so S2 is sufficient.
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