Find Volume of Composite Figures Practice Test

A swimming pool consists of a shallow end and a deep end, both shaped like rectangular prisms. The shallow end measures $$20$$ feet by $$15$$ feet by $$4$$ feet deep. The deep end measures $$20$$ feet by $$10$$ feet by $$8$$ feet deep. If it costs $$\3.50$$ to heat each $$100$$ cubic feet of water, how much does it cost to heat the entire pool?

A composite solid is made from two non-overlapping right rectangular prisms that meet along a face. Prism A is $9\text{ in} \times 2\text{ in} \times 2\text{ in}$. Prism B is $1\text{ in} \times 2\text{ in} \times 2\text{ in}$. The seam shows the parts do not overlap, so the total volume equals the sum of the parts: $V_{\text{total}}=V_A+V_B$. What is the total volume?