Marbles In A Box

Marbles in a box 

In our maths lesson yesterday we were given a complicated puzzle to solve. We very hard on it trying to figure out the answer, drawing different 3D boxes and sums.  We did figure out the answer after a while but it was a lot of hard work. 

Get out a pencil and paper and see if you can figure out the problem. 

Comment what you think the answer is and I will tell you if it is right.