Question

http://gyazo.com/2c743cd2cebd2b524e0e846b5be7d964

Answer 1

Two cubes, the volumes should be added.
One cube has side 5, so volume is 5^3.
The other cube has side 15, so volume is 15^3.
Add the two volumes to get answer.

Answer 2

so B

Answer 3

It cannot be b because the volume of the small cube alone is
\[5^3=125\]
which is greater than 120 given in B.
Calculate the volume of the individual cubes and add them up.