Question

Red is painted on two opposite sides of a cube and the remaining are blue. It is cut into 64 identical cubes. How many small cubes have either 0 or 2 blue sides? 
1. 24
2. 25
3. 27
4. 30

Answer 1

Correct Answer - Option 1 : 24

Let red be on top and bottom and the remaining sides be in blue.

On cutting it to 64 pieces, it will be a 4 × 4 × 4cube. The centre four pieces on top and bottom has only red and no blue, which accounts for 8 pieces. All the corner pieces has 2 blues, and this is 8 pieces. And all the edge pieces of the middle 2 layers has 2 blues, and this 8 pieces. So 24 pieces in total.

Hence, 24 is the right answer.