Eva's family had a 15,000 gallon swimming pool built. They began filling the pool at 8:00a. m. on Saturday. Every fifteen minutes, Eva recorded the number in the pool. The pool was being filled at a constant rate. The table shows the first 45 minutes of Eva's data.
Gallons
1,000
2,000
3,000
15
30
45
Minutes
At what rate, in gallons per hour, is the swimming pool being filled?
A. 15 gallons per hour
B. 4000 gallons per hour
C. 66.6 gallons per hour
D. 2000 gallons per hour