Principal $12,000, Interest Rate 9%, Time 240 days (use ordinary interest). Partial payments: On 100th day $5,800, on 180th day $3,400. Use the U.S. Rule to solve for total interest cost. (Use 360 days a year. Do not round intermediate calculations. Round your answer to the nearest cent.) Total Interest Cost: ? Use the US Rule to solve for balances. (Use 360 days a year. Do not round intermediate calculations. Round your answer to the nearest cent.) Balance After Payment on the 100th day? Balance after payment on the 180th day?