sud21 wrote:A rectangle is L long and W wide, and has diagonal D. What is the area of the rectangle?
1) L+W=Q
2) D^2=B

Since no values are given here, we can be certain that the statements are NOT SUFFICIENT.
As such the answer is E

A GMAT DS question will not ask you to find some algebraic expression. It will either ask you to determine whether or not something is true, or ask you to find a specific value.

For example, the following would never be a GMAT DS question:

What is area of the circle?
1) the radius has length W
2) the circumference is 2W(pi)

Given this info, we might be tempted to say that, from statement 1, the area of the circle is 2(pi)w^2, but this isn't enough. We need to find the actual value that is the area.
The expression (pi)w^2 is not a value.

Cheers,
Brent