A car travels $60-10t$ miles per hour for $0\le t\le3$ hours. 

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

2. Compute the exact area under the curve.

   Hint (b):

   Break the shape into a rectangle and a triangle and sum the two areas. Or, use the formula for the area of a trapezoid.

3. Explain why it is reasonable to say that the car traveled $135$ miles in those three hours.

   Hint (c):

   Multiply the the units for the "length" and "width".