Well, it is

. That is, the equation is

. The run could be found when y=0, so

or

or

or

. 375 inches. 30 feet means 360 inches, as far as I remember (in my country only metric systems are being used :) ) so it doesn't really work -- the ramp is just a bit too long.
5 * 198 = 990
198
* 5
-------
990
The change would start off as a negative and end as a positive she would end up with $425
Sorry to say this but what do u even mean by HOW DO I ANSWER MY QUESTION