An amusement park charges an entrance fee plus an additional charge per ride that a person goes on. The park would like to model the total amount, a, a person will pay as a function of the number of rides, r, they go on. Amelia went on 7 rides and paid a total of $49.50. Lucas went on 12 rides and spent a total of $67.00. Write the information given as (x, y) pairs where the input is the number of rides and output is the total amount spent. ​