Question

Little wooden cubes each with a side of one inch are put together to form a solid cube with a side of three inches. this big cube is then painted red all over on the outside. when the big cube is broken up into the original little ones, how many cubes will have paint on two sides?

Answer 1

if a bigger cube of side 3 inches had to be formed by placing smaller cubes of sides 1 inch each, there will be 3 cubes per row, like how it is in a 3×3 rubix cube.

only the middle cube on the each edhe will have two sides painted in red.
so the total no. of cubes with paints on two sides will be equal to no. of edges, that is 12.