factors

[anishprabhu]

[cramya]

When u see any number properties question prime factorizing would be a good place to start to see if we can get somewhere(easier to see connections and establish relationships)

450 = 2*5^2*3^2

450y = n^3

When an integer is cubed its distinct prime factors will also be cubed.

2*5^2*3^2 * y = (n)^3

We know y must definitely be 2^2*3*5 since RHS is a cubed term(n)



So I must definitely be an integer since its a must be true. The other could be but we focus on the must be true part which leads us to just I

Hope this helps!

Regards,
CR

[brotherwo]

I am losing you on this one..sorry, how do you elimate the other two options. Thanks!

[cramya]

I am losing you on this one..sorry, how do you elimate the other two options. Thanks!

y at a minumum needs to be 2*2*3*5 based on the constraint 450y=n^3 and since the question which of the following "must be" the answer is just I

Search for could be true and must be true questions on this forum and u will find the difference in the answer choices that need to be picked. I have seen quite a few GMAT PREP software questions of this type also

II and III could be integers i.e if y had an extra 3 then II could be and if y had an extra 5 III could be an integer.

Hope this helps!

Regards,
CR