This is a simple question of surface area. It would be easier for you if you drew a diagram of it but even so, the surface area can be calculated by the equation of (8 x 5)+(8 x 5)+(6 x 5)+(6 x 5)+(6 x 8)+(6 x 8)
=(40 x 2)+(30 x 2)+(48 x 2)
=80+60+96
=140+96
=236 inches squared