A solid cube of 4 inches has been painted red, green and black on pair of opposite faces. It has been cut into one inch cubes. How many cubes will have only two faces painted?

Correct option is A

Given:
Original cube edge length = 4 inches
Smaller cube edge length = 1 inch
Formula Used:
Number of smaller cubes along an edge (n) = $$\frac{Large\ Cube\ Edge}{Small\ Cube\ Edge}$$​​
Number of cubes with exactly two faces painted = 12 × (n - 2)
Solution:
Calculate the number of pieces (n) along one edge of the larger cube.
n = $$\frac{4}{1}$$​= 4
Cubes with exactly two faces painted lie on the edges of the original cube, strictly between the corner pieces.
There are 12 edges in a cube.
Number of such cubes = 12 × (4 - 2) = 12 × 2 = 24
Final Answer
So the correct answer is (a)