Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 26 Jun 2016, 21:47

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If n and y are positive integers and 450y=n^3, which of the

Author Message
Intern
Joined: 29 Dec 2007
Posts: 18
Followers: 0

Kudos [?]: 3 [0], given: 0

If n and y are positive integers and 450y=n^3, which of the [#permalink]

Show Tags

17 Feb 2008, 08:49
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Anyone can help? I can't figure this out...

******

If n and y are positive integers and 450y=n^3, which of the following must be an integer?

1. y/(3 x 2^2 x 5)

2. y/(3^2 x 2 x 5)

3. y/(3 x 2 x 5^2)

A. 1 only

B. 2 only

C. 3 only

D. 2 and 3

E. 1, 2 and 3
Intern
Joined: 07 Jan 2006
Posts: 49
Followers: 0

Kudos [?]: 4 [0], given: 0

Show Tags

18 Feb 2008, 02:00
n^3 must end in 0 to meet any integer multiplier of 450, so just need to test any number in multiples of 10.

n^3 must be divisible by 450.

The lowest number do-able is 30, so 30^3 = 27000

lowest of y = 27000/450 = 60

...so y must be at least divisible by 60, so y/60 must be an integer.

but if y is 60, then y/90 and y/150 are not integers...

A.
Senior Manager
Joined: 15 Aug 2007
Posts: 252
Schools: Chicago Booth
Followers: 1

Kudos [?]: 61 [0], given: 0

Show Tags

18 Feb 2008, 09:45
Agree with A.

prime factors of 450 are 3^2, 5^2 and 2. in order to make y = n^3/450 an integer, since n is a power of 3 all primefactors of n should raise to 3. so 3*5*2^2 should be part of n^3.
Re: DS integers   [#permalink] 18 Feb 2008, 09:45
Display posts from previous: Sort by