(1) we could pick y=2, x=1 and z=4 to get a "yes" answer or y=2, x=4 and z=1 to get a "no" answer.. insufficient.cramya wrote:If X, Y, and Z are positive integers, is Y>X?
(1) Y^2=XZ
(2) Z-X>0
(2) No info about y, insufficient.
Together:
From (2), we know that z>x. So:
y*y = (x)(more than x)
Since all the variables must be positive, the only way that equation can hold true is if y>x. Choose (C).
Another way we could look at it is to say that z = x + k, in which k is a positive integer. So:
y^2 = x(x+k)
y^2 = x^2 + xk
Since y^2 equals x^2 PLUS something else, y^2 must be greater than x^2, and since x and y are both positive, y > x.
I was looking for different approaches and got one.
