A21,000 gallon swimming pool contains 9000 gallons of water when a hose is placed into the pool and begins adding water at a rate of 1500 gallons per hour.

plot a graph representing the volume of water in the pool over time from when the hose is placed into the pool until it is full.

If the rate at which the swimming pool is filling is 1500 gallons per hour, and the pool has already 9000 gallons full, then;

Amount to be filled is 21,000 – 9,000 = 12, 0000

To fill the 12,000 gallons;

12,000/1500 = 8 hours

If the filling of the pool begins at 12.00 AM, then the pool will fill at 8.00 AM