On the Allied Students Cell Phone plan:
If you use 60 minutes or less in a month you pay $17.99 in usage charges. If you use between 60 and 120 minutes you pay the $17.99 plus $0.25 per minute for each minute over 60 in usage charges. If you use more than 120 minutes you pay $29.99 plus $0.15 per minute for each minute over 120 in usage charges. In addition, there are a $7 processing charges per month. Then there is an 8% sales tax on all charges.
Create a worksheet that allows you to enter the minutes used and then shows you the usage charge, the processing charge, the tax, the total charge, and the average total cost per minute. Try your worksheet with inputs of 10 minutes, 100 minutes, and 5000 minutes.