Suppose you have an existing credit balance of $$1000$ from the vacation trip to Romania at the end of August. The annual interest rate is $18\%.$ On August $15,$ you used your credit card to pay for a $$175$ car repair, and on August $28,$ you make a payment of $$700.$ Answer the following questions.

a$)$ Calculate the finance charge that will appear on the statement for next month using the unpaid balance method and average daily method.

b$)$ Would it have been better to pay $$700$ on August $16?$ Justify your answer.

c$)$ If you do not want the finance charge not more than $$5,$ what should you do$?$