A wood of block measuring 5 in. by 6 in. by 7 in. is painted blue. It is then completely cut to cubes which measure 1 in. on an edge. How many cubes have 1 blue face?
On the top we have (6 - 2) (7 -2) = 4 * 5 = 20
On one side we have (5 - 2) (7 - 2) = 3 * 5 = 15
On the front we have (5 - 2) ( 6 - 2) = 3 * 4 = 12
So doubling each of these we have
2 ( 20 + 15 + 12) =
2 ( 47) =
94
