A cell phone plan has the following charges:
Basic service, including 100 minutes of calls :$20 per month
2nd 100 minutes of calls: $0.075 per minute
Any additional minutes: $0.10 per minute
What is the charge for 200 minutes of calls?
What is the charge for 250 minutes of calls?
Construct a piecewise function that describes the monthly charge C for x minutes of call.