The table below shows the total number of hamburgers sold at various times during the day for a popular fast food restaurant. Assume the function used to model the data in the table is a continuously increasing function.

1. At approximately what rate were hamburgers being sold at 10 a.m.? 4p.m.?

   Step (a):

   $h^\prime\approx\frac{39-3}{11-9}$

2. For what time interval was the rate of sales greatest?

   Hint (b):

   Use the eTool below to help solve the problem.
   Click on the link to the right to view the full version of the eTool. Calc 11-98 HW eTool