last weird question

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last weird question

by flystud777 » Sat Sep 06, 2008 9:01 pm
explanations? i see 1 is sufficient. prime factors of 70 are 2, 5, 7

what about 2nd statement? why is that not sufficient? prime factors of 10 are 2 and 5. no other factors (i.e. 10 and 1 don't count as it says integers greater than 1)

any help would be appreciated.
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Re: last weird question

by parallel_chase » Sun Sep 07, 2008 12:39 am
flystud777 wrote:explanations? i see 1 is sufficient. prime factors of 70 are 2, 5, 7

what about 2nd statement? why is that not sufficient? prime factors of 10 are 2 and 5. no other factors (i.e. 10 and 1 don't count as it says integers greater than 1)

any help would be appreciated.
Statement I

xyz=70 = 2*5*7

There is no other way 70 can be product 3 integers without using 1.

Therefore, x+y+z = 14

Sufficient.

Statement II

10x = 7yz

CASE I

x = 14, y=4, z=5

yz = 20 = 4*5

10*14 = 7*4*5

There is no restriction in the question why x cant be 14

CASE II

x=7, y=2,z=5

7*10 = 7*2*5

Similarly, we can have infinite values for x , y and z Insufficient.

Hence A is the answer.

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by flystud777 » Sun Sep 07, 2008 11:56 am
got it. thanks.