Question

The table below shows how the number of hours needed to fill a pool depends on the flow rate of the hoses used to fill it.

Flow rate, x
(gal/hr)
Time, y
(hours)
60
300
45
400
36
500
30
600

How long will it take to fill the pool if two hoses are used, one that fills at a rate of 40 gallons per hour and one that fills at a rate of 60 gallons per hour?
100 hours
150 hours
180 hours
200 hours

Answer 1

Flow rate × time is constant (pool volume): 60·300 = 45·400 = 36·500 = 30·600 = 18,000 gallons.

Two hoses: 40 + 60 = 100 gal/hr. Time = 18,000 ÷ 100 = 180 hours.

Answer: 180 hours.