benjiboo wrote:Is x < z?

(1) x = (1/2)y

(2) y = 0.5z

Is it proper to say: (answer and question below, incase you wanted to try it out first)

[spoiler]2x=y
2y=z
so therefore...
4x=z

And the answer is E because if x=1, z=4, but x and z could both be zero... Or is this not what is actually being tested?[/spoiler]

Your answer of E is correct, but you do need to determine the sufficiency of each statement alone before combining them to get 4x = z

My solution.

Target question: Is x < z?

Statement 1: x = (1/2)y
This tells us the relationship between x and y, but since there is no mention of z, there is no way to tell whether or not x is less than z.
INSUFFICIENT

Statement 2: y = 0.5z
This tells us the relationship between y and z, but since there is no mention of x, there is no way to tell whether or not x is less than z.
INSUFFICIENT

Statements 1 & 2:
If y = 0.5z and x = (1/2)y then we can conclude (as you have done) that 4x = z
Is this sufficient to answer the target question with certainty? No.
If 4x = z, there are several possible cases to consider. Here are two:
case a: x=1 and z=4, in which case x is less than z.
case b: x= -1 and z= -4, in which case x is not less than z.
INSUFFICIENT

Answer = E

Cheers,
Brent