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# If M and N are positive integers,is MN/15an integer 1.THE L.C.M of M a

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Joined: 17 May 2017
Posts: 151
GPA: 3
If M and N are positive integers,is MN/15an integer 1.THE L.C.M of M a [#permalink]

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28 Oct 2017, 02:39
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65% (hard)

Question Stats:

45% (01:06) correct 55% (01:49) wrong based on 20 sessions

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If M and N are positive integers, is (MN)/15 an integer

1.THE L.C.M of M and N is 80
2.The greatest common factor of M and N is 4
[Reveal] Spoiler: OA
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Joined: 25 Feb 2013
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If M and N are positive integers,is MN/15an integer 1.THE L.C.M of M a [#permalink]

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28 Oct 2017, 02:57
haardiksharma wrote:
If M and N are positive integers, is (MN)/15 an integer

1.THE L.C.M of M and N is 80
2.The greatest common factor of M and N is 4

For $$MN$$ to be divisible by $$15$$ between them they must have at least one $$3$$ & $$5$$ as a factor

Statement 1: implies that neither $$M$$ nor $$N$$ has $$3$$ as a factor. Hence $$MN$$ will not be an integer. Sufficient

Statement 2: this does not provide any information about all the factors of $$M$$ & $$N$$. Let $$M=12$$ and $$N=40$$, then HCF will be $$4$$ and $$MN$$ will be divisible by $$15$$

but if $$M=4$$ and $$N=8$$, then HCF will be $$4$$ but $$MN$$ will not be divisible by $$15$$. Hence Insufficient

Option A
If M and N are positive integers,is MN/15an integer 1.THE L.C.M of M a   [#permalink] 28 Oct 2017, 02:57
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