Cube problems

[Hi2All]

A hollow cube of size 5cm is taken , with the thickness of 1cm . it is made of smaller cubes of size 1cm . if the outer surface of the cube is painted how many faces of the smaller cubes remain unpainted?

[pscoe2]

438...
total number of faces=588...
surface area painted=6*5*5 cm2=150 cm2
which is equal to 150 faces of 1*1 cm2
painted faces=588-150 = 438....

[chandrakaladhar]

Please explain me how to solve this problem......

There are two cubes A and B. Each of it is cut into 64 pieces. From the front face of cube A cubes on both the diagonal are removed. Same is repeated with Cube B. Now Cube A is placed over cube B to form a rectangular cuboid and painted black.
1. The no. of cubes that are not painted black?
2. The no. of cubes that are one side painted black?
3. The no. of cubes that are two sides painted black?
4. The no. of cubes that are three sides painted black?

Waiting for the reply........

[kcscm]

A bid red cube is divided into 1000 smaller cubes .From the second column of the front face,from the left all cubes are removed .The entire structure is then painted black.


1.what is the difference between the number of cubes colored red on 3 faces and the number of cubes colored black on 3 faces.?

similarly for 2 faces and 1 face.

please give the solution friends...