From stmt1,

200/100*x=400/100*y

x=2y,We dont know value of y,Insufficient.

From stmt2,

xy=a^2

xy=9 or xy=16 or ...,Insufficient.

Combining 1 and 2

2y^2=a^2

Many scenarios are possible for this condition..

Insufficient.

Hence E

Haaress wrote:Q. If x and y are positive, what is the value of x?

a) 200% of x is 400% of y
b) xy is the square of a positive integer

i saw this question on the web, but don't know what he OA is. Can someone confirm the OA from OG 10.

2x=4y
x=2y
INSUFF

xy =k^2
again x can be any value.
INSUFF

Combining:
x=2y
1/2 *x^2 = K^2
K is positive integer.
if K=1, x=1/root(2)
if k=2, x = 2root(2)

INSUFF

I do not know the OA. But I believe the answer should be E

Haaress wrote:Q. If x and y are positive, what is the value of x?

a) 200% of x is 400% of y
b) xy is the square of a positive integer

i saw this question on the web, but don't know what he OA is. Can someone confirm the OA from OG 10.

The answer is definitely E.
(1) 2x = 4y, so x=2y. No idea what the values are.
(2) doesn't give us any specific values to work with.

MERGE STATEMENTS
Replace x with 2y. Statement 2 then says 2y*y is the square of a positive integer. There are an infinite number of values. 2y*y could equal 1 >> y=root(1/2). or 2y*y could equal 4 >> y=root(2). Notice that we are never told that x and y are integers.

Haaress, let me go get my OG 10. I'll tell you the OA... The OA is E

Hope that helps,
Patrick