Question

A cube of side 3 cm is painted black on the pair of one opposite surfaces, blue on the pair of another opposite surfaces and red on remaining pair of opposite surfaces. The cube is now divided into smaller cubes of equal side of 1 cm each.

How many smaller cubes have two surfaces painted?

• A. $36$
• B. $60$
• C. $12$
• D. $24$

Answer 1

The correct option is C $12$

Top surface has 4 small cubes having colour on three faces.

Same for the bottom surface.

Front and back surfaces has $2+2$ i.e. 4 small cubes with three faces painted.

So, total $12$ cubes have colour on three faces.

Hence, option C is correct.