Ronnie has a credit card that uses the previous balance method. the opening
balance of one of his 30-day billing cycles was $4790, but that was his
balance for only the first 4 days of the billing cycle, because he then paid off
his entire balance and didn't make any new purchases. if his credit card's apr
is 15%, which of these expressions could be used to calculate the amount
ronnie was charged in interest for the billing cycle?