Gavin has a smart phone data plan that costs $20 per month that includes 6
GB of data, but will charge an extra $10 per GB over the included amount.
How much would Gavin have to pay in a month where he used 2 GB over the
limit? How much would Gavin have to pay in a month where he used went
over by x GB?
Total cost when over by 2 GB:
Total cost when over by x GB: