Marlene has a credit card that uses the adjusted balance method. for the first 10 days of one of her 30-day billing cycles, her balance was $570. she then made a purchase for $120, so her balance jumped to $690, and it remained that amount for the next 10 days. marlene then made a payment of $250, so her balance for the last 10 days of the billing cycle was $440. if her credit card's apr is 15%, which of these expressions could be used to calculate the amount marlene was charged in interest for the billing cycle?