Data Sufficiency

20)

If X and Y are integers greater than 1, is X a multiple of Y?

1) 3Y^2 + 7Y = X
2) X^2 - X is a multiple of Y.


Thanks in advance!

Ans (A) ?

Yes I got (A) too.

It is really asking if x/y is an integer.

3Y^2 + 7Y = X

so Y(3Y+7)/Y = Integer? Yes

Choice 1 works.

choice 2 tells us that (X^2 - X)/Y = integer.

We can't be sure b/c X(X-1) = X^2 - X

either X can be divisible by Y or (X-1) can be divisible by Y or both X and (X-1) are divisible by Y

A is the answer. Thanks a lot