If y > 0, then x is what percent of y?

(1) y = 5x --> x = y*1/5 = y *20/100, so y is 20% of x. Sufficient.

(2) x = 5. Nothing about y. Not sufficient.

Answer: A.
_________________

the question is asking for the ratio of x and y..
1) statement one gives us the relation between x and y in terms of ratio... sufficient..
2) statement just gives us value of x, nothing about y... insufficient
ans A
_________________

Hi pinkcupcake,

As Bunuel and chetan2u have pointed out, this question is essentially just about ratios. If you haven't mastered that concept yet, then that's okay, but you will be tested on it repeatedly on the Official GMAT, so the concept is worth some extra practice.

If you don't immediately see the ratio "pattern" in this question, then you can still get to the correct answer by TESTing VALUES and proving that a pattern exists.

We're told that Y is positive. We're asked about how X and Y relate to one another - specifically 'X is what percent of Y?'

Fact 1: Y = 5X

IF....
X = 1
Y = 5
1 is 1/5 of 5; 1/5 = 20%

IF....
X = 2
Y = 10
2 is 2/10 of 10; 2/10 = 20%

IF....
X = 2.5
Y = 12.5
2.5 is 2.5/12.5 of 12.5; 2.5/12.5 = 1/5 = 20%
Etc.

There's clearly a pattern here; X is 20% of Y.
Fact 1 is SUFFICIENT

Fact 2: X = 5

This tells us nothing about Y, so we cannot answer the question.
Fact 2 is INSUFFICIENT.

Final Answer:

GMAT assassins aren't born, they're made,
Rich
_________________

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________