A cell phone plan has a monthly cost that is shown in the table below. What is the correct statement regarding the average rate of change during the 40-minute time of talk?

Monthly cost of cell phone for 0 minutes is $19.95 and for 40 minutes of talk is $21.95. It means that average rate of change (increase of monthly cost for each minute of talk time) is: ARC = (21.95 - 19.95) / (40 - 0) = 2.00 / 40 = $0.05. Answer: C) The average rate of change is $0.05, meaning that for each minute of talk time, the monthly bill increases by $0.05.