Use the unpaid balance method to find the finance charge on the credit card account. Last​ month's balance, the​ payment, the annual interest​ rate, and any other transactions are given. Last​ month's balance, ​$480 ​Payment, ​$340 Interest​ rate, 17.8% Bought plane​ ticket, ​$190 Bought​ luggage, ​$110 Paid hotel​ bill, ​$160