<span>Given:
C -> Umesh's total charge in dollars.
h -> the number of hours he spends on a job.
Hourly charge =$80 /hr
Charge for h hours = 80*h
fixed charge per job = $50
Therefore, C = 80h +50 is the required equation to find the total charges</span>
So you start off with $21.50. Subtract $4 from 21.50 and you'll end up with $17.50. Now divide $17.50 with the price of each ride which is $2.50 and you end up with 7. You are able to go on 7 rides.