Question

If 1 cube is painted black and it is cut into 125 identical cubes . Then in the cubes obtained how many of them are not painted?

Answer 1

Number of the cubes not painted are 27

Answer 2

Solution :-

The question says that 1 cube is painted black and it is into 125 identical cubes.

Since, 125 = 5³, it implies that each side of the large cube is actually made up of 5 cubes. The sides of the inner cube are built with 3 small cubes (5 - 2 small edge cubes). 

So, the number of cubes painted black = 125 - 3³

= 125 - 27

= 98 cubes are painted black.

So, the number of cubes which are not painted black = 125 - 98 

= 27

Answer.