It's raining outside, and after 1 hour of rain, the water level in jake's pond is 2 meters. after 3 hours, the water level is 2.8 meters. find the rate of change.

The rate of change is 0.4 meters per hour:

There is a difference of 0.8 between the measurements, and the time it took to change that was 2 hours, so if you divide 0.8 by 2, you get 0.4 per 1 hour.