It gained 2 lb. because if you subtract 8-6 you would get 2. So Arfus gained 2 lb.
The volume of this prism is: 240 cm3.
Because, in order to find the volume you have to do: V = w h l = 4 x 15 x 4 = 240.
(V = volume, w = width, h = height, and l = length)
Hope I helped!
- Amber
