Question

The following data table represents the total cost of a monthly cell phone bill as a function of the number of minutes that the phone is used each month.


Minutes 500 750 1,000 1,250 1,500
Total Monthly Cost (in dollars) $62 $77 $92 $107 $122
Choose the correct linear model that represents the total monthly cost as a function of time.
y = 62 x + 16
y = 16 x + 32
y = 0.06 x + 32
y = 0.06 x + 500

Answer 1

First find the slope: (77−62)/(750−500) = 15/250 = 0.06.
Use (500,62): 62 = 0.06(500) + b → b = 32.

So the correct model is y = 0.06x + 32.