Question

What is the surface area of the composite figure?

Answer 1

first you need to split both figures up

Answer 2

Probably the fastest way is to do what @Outkast3r09 suggests. Split the figure into two rectangular boxes, one that is 5 by 5 by 10 and the other is 5 by 5 by 20. What would the surface area of those two boxes be?

Answer 3

Then you would have to subtract the area of the part that overlaps, which would be an area that is 5 by 5.