The volumes of two cylindrical cans of the same shape vary directly as the cubes of their radii. If a can with a six-inch radius holds 1½ pints, how many gallons will a similar can with a 24-inch radius hold?

Answer 1

24/6 = 4
4^3 = 64

64 * 1.5 = 96 pints

there are 8 pints per gallon so
96/8 = 12 gallons

Answer 2

change pints to gallons.
1 1/2 pints = 3/16 gallon

3/16 x
_____ = ____ create proportion.
6^3 24^3

6^3 * x = 24^3 * 3/16
216 * x = 13824 * 3/16 simplify
216 * x = 2592 divide both sides by 216
x = 12 gallons