What percent is x of y?

[mcmebk]

What percent is x of y?

(1) x = 3y

(2) x "” y = 6

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
Both statements TOGETHER are sufficient, but NEITHER one ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.

Does X, Y always mean different numbers? if they both can be 0, then the answer should be C.

Thanks.

[RonPurewal]

They can't be 0; that would require us to calculate the quotient 0/0, which doesn't exist.
Remember that "undefined" quantities do not count as counterexamples; they just don't count as anything at all. Because they're not defined. You can just ignore them.