Need help with A and B

An installment contract for the purchase of a car requires payments of $278.33 at the end of each month for 3.5 years. Interest is 9% per annum compounded monthly (a) What is the amount financed? (b) How much is the interest cost? (a) The amount financed is $ (Round the final answer to the nearest cent as needed. Round all intermediate values to six decimal places as needed.)