Elisa withdrew $20 to equal $140 if you divide 140/20 is how much times she withdrew was a total of 7. While the same with with Francis except his total was almost 7 with it being 6.75
The graph would be linear since it's .05 every minute, which would mean that every minute it would cost .05 --> adding up minutes. The flat fee at the beginning is trying to trick you up, don't get fooled ;)
