Question

Katelyn is shopping for a cellular phone service. Trenton bell charges a monthly fee of $40 for up to 500 minutes. For every minute over 500 there is an $0.18 charge. Write a piecewise function to represent the cost of this plan

Answer 1

For this case, the first thing we must do is define variables.
 We have then:
 x: number of minutes.
 y: total cost.
 We then have a function for two different intervals.
 These intervals are:
 For $0 \leq x \leq 500$:
 $y = 40$
 For $x\ \textgreater \ 500$:
 $y = 0.18x + 40$