The volume is 640 ft3.
To find a volume of a rectangular prism is: [tex] V=lwh [/tex]
Length: 8 feet
Width: [tex] 2w=8 \:\:\:\:\:\:w=\frac{8}{2} \:\:\:\:\:\: w=4 [/tex]
Height: [tex] h=\frac{5*8}{2}\:\:\:\:\:\:2h=40\:\:\:\:\:\:h=20 [/tex]
Plug in the values and solve: [tex] V=8*4*20=640 [/tex]
