If the tank is full with gas she can drive 240 miles (or 20 times/days to and from work) I guess you have forgotten to write the question, but I hope this i what you are looking for. If not, let me know so I can help you further. Enjoy your day.
Use the equation 15000(1.07)^5 since 1.07 equals to 7% and you are loaning more money to Tony's account for 5 years. You should get $21,038.28 as your result.