The amount of data left on a cell phone plan is 6 GB after 8 days. 1.5 GB of data is used each day. How much is a available at the beginning of the cycle?
All we have to do is add 1.5 GB per day times the 8 days that's already happened to the current 6 GB, and so it looks like this: 8(1.5)+6 12+6 18 GB at the beginning of the cycle