In the city of Carmen, there is a drawbridge that is opened twice per hour over the summer. The graph below shows the number of feet that the top of the bridge was above the water versus the amount of minutes that the drawbridge was open.
40
30
Feet Above Water
20
10
3
Minutes
The city's engineer noticed that the bridge is not opening and closing at the same rate and wanted to determine the rate of change over these intervals. Complete the table to determine the rate of
change for the drawbridge (in feet per minute) at each of the specified intervals.