need help with these simple interest

Automotive Excellence Inc. borrowed $17,000.00 on April 8 with an interest rate of 7.4% per annum. On June 17, $5300.00 was repaid, and on August 9, $5100.00 was repaid. Automotive Excellence paid the balance of the loan on December 1. What was the final payment? The final payment was $-1 (Round the final answer to the nearest cent as needed. Round all intermediate values to six decimal places as needed.)Dirk Ward borrowed $12,000.00 for investment purposes on May 10 on a demand note providing for a variable rate of interest and payment of any accrued interest on December 31. He paid $700 on June 10, $150 on September 27, and $1200 on November 8. How much is the accrued interest on December 31 if the rate of interest was 7% on May 10, 7.6% effective August 1, and 7.85% effective November 1? The accrued interest on December 31 is $- (Round the final answer to the nearest cent as needed. Round all intermediate values to six decimal places as needed.)