Question 98667
Your reasoning so far looks good.
How many trips before the costs are the same?
5.50 + .35t =.50t
5.50 + .35t - .35t =.50t - .35t
5.50  =.15t
t=5.50/0.15
t=36.67
The costs will be the same for 36 and two thirds trips. Any more than that and you are ahead on the cost of the sticker.
So you are ahead on the 37 th trip.