Joey has a credit card that uses the previous balance method. The opening balance of one of his 30-day billing cycles was $0, bu
t this was his balance for only the first 15 days of the billing cycle. He then made a purchase that increased his balance to $7200, and his balance stayed this amount for the remainder of the billing cycle. If his credit card's APR is 13%, how much was Joey charged in interest for the billing cycle?
