(Note that your answer is an algebraic expression involving $d$).
A circular swimming pool has a depth $d$ and a radius that equals five times its depth. A rectangular pool has the same depth as the circular pool. Its width is four feet more than three times its depth and its length is two feet less than six times its depth. The ratio of the rectangular pool's volume to the circular pool's volume is .
Hint: The volume of each pool equals the product of its depth and the area of its cross section. The area of a circle with radius $r$ equals $\pi r^2$. The area of a rectangle with sides $a$ and $b$ equals $ab$.