tough question - GMAT Prep

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tough question - GMAT Prep

by san2009 » Thu Jul 15, 2010 12:11 am
If x is a positive integer and x is less than or equal to 30, what is the value of x?

(1) x can be written as the product of 3 different prime numbers each of which is greater than or equal to 2.

(2) x is divisible by 3 and 5.


My approach:
rephrased original question
0<x<=30
x=?

1) x=2*2*2=8
x=2*3*3=18
x=2*2*3=12
x=2*3*5=30
clearly statement 1 is insuff

2) x could be 15 or x could be 30
insuff

1+2= the only common value of x between statement 1 and statement 2 is 30
thus x=30
sufficient
my ans: C

OA is A

help!
Source: — Data Sufficiency |

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by clock60 » Thu Jul 15, 2010 12:22 am
hi friend
we are given that x is product of 3 different numbers
so it cannot be 2*2*2
it can be 2*3*5 only as 2*3*7 is more than 30
so x has unique value x=2*3*5
from 2 st we know that x is 15, or 30
so insufficient

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by san2009 » Thu Jul 15, 2010 12:35 am
crap. thanks dude. i guess im still v prone to careless/meaningless mistakes