The key to answering this question is to realize that you have two polyhedrons combined to form one thus the overall volume would be equal to the sum of the two polyhedron.
Total volume= (volume of prism) + (volume of cuboid)
a) Volume of cuboid (
)=
l = 13ft
w = 18ft
h = 21ft
: .
= 13ft * 18 ft * 21ft
= 4914
b) Volume of Prism (
) =
b = 18ft
h = 16ft
H = 13ft
: .
=
= 1872
Thus Overall Volume = 6786