Question

The amount of data left on a cell phone plan is 6GB after 8 days. 1.5 GB is used every day. How much is available at the beginning of the cycle?

Answer 1

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