Answer:
24 g
Step-by-step explanation:
hello,
The big cube is compose by the 8 small cubes.
Because of the symmetry we can check what's happening to one of this small cube.
As Amanda has already painted the big cube it means that the same cube has 3 faces painted, so 3 faces are left unpainted. only 50 % is painted.
so Amanda need 24 grams to paint the unpainted surfaces of the 8 cubes.
hope this helps