Solve for n in 270=120 + n*10. 120 gives you first 30 minutes and n is the number of additional 10 minutes you ride. In this case you ride for 30+n*10 minutes. n = (270-120)/10 = 15. So the total time is 30+15*10 = 180 minutes. Or three hours!! That’s a lot of bumper cars!!
