Diane has a credit card that uses the unpaid balance method to calculate interest. The annual rate of interest is 18%. At the end of July she did not carry a balance on the card (the unpaid balance is $0). She made the following purchases and payments in August: Purchased gifts for her mom's birthday totaling $78 Purchased shoes and a sweater for $86 Returned the shoes, totaling $24 Purchased groceries for $130 Made a payment of $50 Using the unpaid balance you found in a previous problem, find the finance charge at the end of August