Answer:
2 2/3 ft/month (increasing)
Step-by-step explanation:
The water level in the 2nd month is 30 ft.
The water level in the 8th month is 40 ft. That is 6 months later.
The water has risen (40 -30) = 10 ft in (8 -2) = 6 months. That is an average rate of change of (10 ft)/(6 mo) = 5/3 ft/mo.
The average rate of change was an increase of 2 2/3 feet per month.
