What is the variable needed to answer the question? Is this an independent or a dependent variable?

Many amusement parks have started selling annual passes. If a person has an annual pass, then they can enter the park at any time without having to buy a ticket. A famous amusement park charges $109 for a one-day ticket and $1,300 for an annual pass. The cost to park your vehicle at the park is $35 a day but annual pass holders do not have to pay to park. You have several days for a vacation and want to spend them at the amusement park When would it be cheaper to buy an annual pass rather than paying per day