2. Use the graph below to answer the following questions. (You must include the units).

The amount of water in a small lake in Virginia is changing at the rate modeled by the graph
below. The rate is measured in cubic inches per hour.

a) After the first 5 hours, how much water has been gained/lost in the lake? (Show all work 4
points).

b) After 13 hours, how much water has been gained/lost in the lake? (Show all work 4 points).