Question 2.57

2.57 Compare the cell phone payment plans

A cellular telephone company offers two plans. Plan A charges $30 a month for up to 120 minutes of airtime and $0.55 per minute above 120 minutes. Plan B charges $35 a month for up to 200 minutes and $0.50 per minute above 200 minutes.

  1. Draw a graph of the Plan A charge against minutes used from 0 to 250 minutes.
  2. How many minutes a month must the user talk in order for Plan B to be less expensive than Plan A?