Mr. Daniels bought an above-ground cylindrical swimming pool that has a diameter of 20 feet. He wants to know how long it will take to fill his pool to a depth of 4 feet using his garden hose. It takes him 15 seconds to fill a one-gallon jug. (Note: 1 gallon = 231 cubic inches.)

Answer 1

Time*rate=volume

time=volume/rate=PI*(10)^2 *4 ft^2/rate

now rate is 1gal/15sec*1ft^3/7.48gal * 3600second/hr
rate= 3600/(15*7.48)

so
time=400PI/(3600/(15*7.48))
time=400PI*15*7.48/3600 hr