How much water, to the nearest gallon, is in the tank at time t = 10 minutes (calculus help please)

Question

Water flows into a tank according to the rate  , and at the same time empties out at the rate  , with both F(t) and E(t) measured in gallons per minute. How much water, to the nearest gallon, is in the tank at time t = 10 minutes. You must show your setup but can use your calculator for all evaluations. 

Answer 1

The net flow in is F(t) - E(t) so you need to integrate F(t) - E(t) from t=0 to t=10.

You can do this directly on a TI-84.