Question

A cube of $4cm$ has been painted on its surface in such a way that two opposite surfaces have been painted blue and two adjacent surfaces have been painted red. Two remaining surfaces have been left unpainted. Now the cube is cut into smaller cubes of side $1cm$ each. How many cubes will have three surfaces coloured?

• A. $3$
• B. $4$
• C. $2$
• D. $16$

Answer 1

Answer: (C)

$2$

Total number of smaller cubes
$=\frac{4\times 4\times 4}{1\times 1\times 1}=64$
$n=\frac{sideofbigcube}{sideofsmallcube}=\frac{4}{1}=4$.
Number of smaller cubes having $3$ surfaces coloured = Number of smaller cubes at $2$ corners $=2$.