MGMAT - Properties

[Ves]

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

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


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

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


Ans: I only

Can you please explain the answer?

Thanks

[Ves]

Source is GMAT Prep

[aryan]

since n^3=450y
n=cube root(2*5^2*3^2*y)

as n is integer so y=2^2*5*3 it is minimum there may be other value which must be multiple of 60.
hence the ans is y/3.4.5

[Ves]

Thanks a lot Aryan!

[RonPurewal]

people!
"450y" is the world's greatest search term. type it into the box and watch at least 3 old threads come up.
i understand that the search box is obstreperous at times, especially when the search string contains rather generic terms (a fair number of math problems don't really contain anything other than numbers and letters, making searches difficult), but you should have no trouble finding this one.

http://www.manhattangmat.com/forums/if- ... t4311.html

http://www.manhattangmat.com/forums/if- ... -t279.html