The Gladiator van travels $20t + 18$ miles per hour for $0\le t\le3$ hours.

1. Draw a graph of the situation. Label the axes carefully.

2. Compute the exact area under the curve.

   Hint (b):

   Use the formula for the area of a trapezoid.

3. How far did the Gladiator travel during those three hours?

   Hint (c):

   It is the area under the curve.