Ellen has a movie rental card worth $225. After she rents the first movie, the card’s value is $221.75. After she rents the second movie, its value is $218.50. After the third rental, the card is worth $215.25. Assuming the pattern continues, write an equation to define A(n), the amount of money on the card after n rentals. Ellen rents a movie every Saturday night. How many weeks in a row can she afford to rent a movie, using her rental card only?