Question:
The figure below shows a grey cube and a white cube. The length of each edge of the grey cube is twice that of the white cube. Xin Neng wants to use 5 grey cubes and the least number of white cubes to build a new cube.
(a) How many white cubes does Xin Neng need to build the new cube?
(b) Given that the volume of the new cube is 1728 cm³, find the length of the edge of the white cube.