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