PS question from GMAT PREP test

This topic has expert replies
Source: — Problem Solving |

User avatar
Master | Next Rank: 500 Posts
Posts: 418
Joined: Mon Feb 26, 2007 6:41 pm
Thanked: 24 times

Re: PS question from GMAT PREP test

by Prasanna » Tue Jun 12, 2007 5:03 pm
Fab_Vr6 wrote:If n and y are positive integers, and 450y= n^3, which of the following must be an integer?

I) y/(3x2^2 x5)

II)y/(3^2 x2x5)

III) y/(3x2x5^2)

A) none
B)I only
C)II only
D)III only
E) I II III
Here 450n should be a cube of an integer. 450 can be factorized as 5*5*3*3*2. For 450y to be a cube y could be equal to 5*3*2*2. From this we know y/(3*2*2*5) will be an integer definitely. Hence option B.

Whats the OA?

User avatar
Community Manager
Posts: 789
Joined: Sun Jan 28, 2007 3:51 pm
Location: Silicon valley, California
Thanked: 30 times
Followed by:1 members

by jayhawk2001 » Tue Jun 12, 2007 8:54 pm
Another vote for B.