10. Dirk Ward borrowed $13,000.00 for investment purposes on May 24 on a demand note providing for a variable rate of interest and payment of any accrued interest on December 31. He paid $900 on June 7, $100 on September 14, and $1000 on November 18. How much is the accrued interest on December 31 if the rate of interest was 7% on May 24, 7.4% effective August 1, and 7.75% 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.)