Answer:
10 inches per hour
Step-by-step explanation:
The water level was 13 inches at 1 PM. In 30 minutes (So in 1:30 PM) the water level was 18 inches, so it had increased by 5 inches in 30 minutes (Which is 10 inches in 1 hour). The rate of change is how much it has risen per time, we can also check that between 1;30 pm and 2:30 pm, which are 1 hour apart, the water level had risen from 18 inches to 28 inches, which is 10 inches in an hour.
