A rectangular prism 3cm x 5cm x 8cm is painted mauve and is then cut into 1cm^3 cubes. What is the total unpainted surface area of these cubes?
+37146 painted surface 3 x 5 x 2 + 5 x 8 x 2 + 8x 3 x 2 = 158 cm2 = 158 painted surfaces
total cubes 3 x 5 x 8
total surfaces 3x 5 x 8 x 6 =720 sufaces
unpainted = 720- 158 = 562 unpainted = 562 cm2
