Please help check my answers

Sketch the regions enclosed by the given curves. Decide whether to integrate with respect to *x* or *y*. Draw a typical approximating rectangle and label its height and width.

y= sqrt[x]

y=(1/2)x

x=16

I keep on getting 328/3 as my answer, but when I input it the answer is wrong. I solve the integral in terms of dy but I always get it wrong.

http://i51.tinypic.com/4q0uaw.png

(d) Estimate the time *t* at which the cars are again side by side.

I keep on getting 2.2s but I input it and it ends up wrong.