Problem Solving

Marty has a right circular cylindrical pool of diameter 12 feet and his neighbor, Rusty, has a right circular cylindrical pool of diameter 18 feet. If the depths of the pools are equal, then the volume of water in Rusty's pool is how many times that in Marty's pool?

A. 1.5
B. 2.25
C. 2.5
D. 4
E. 4.25

Answer: B

Source: Princeton Review

Volume(v) = \(\pi\) r \(^{r^2}\) h
r1= 6
r2 = 9
height of both pools is equal
we have to calculate v2/v1
= \(^{r1^2}\) / \(^{r2^2}\)
= 81/36
=2.25