The six faces of a three-inch wooden cube are each painted red. The cube is then cut into one-inch cubes along the lines shown in the diagram. How many of the one-inch cubes have red paint on at least two faces?

8 on top level will have paint on at least two faces

4 on the middle level will have paint on at least two faces

8 on the bottom level will have paint on at least two faces

So

8 + 4 + 8 = 20