Question

A plumber charged $110 for a three-hour job and $160 for a five-hour job. What’s the average rate of change in terms of dollars per hour

Answer 1

The average rate of change is the ratio between the change of each magnitues. The following formula helps to calculate it

`r=(\Delta y)/(\Delta x)`

Using the given information, we have

`r=(160-110)/(5-3)=(50)/(2)=25`

Therefore, the average rate of change is $25 per hour.