Dirk Ward borrowed $12,000.00 for investment purposes on May 8 on a demand note providing for a variable rate of interest and payment of any accrued interest on December 31. He paid $600 on June 13, $200 on September 15. and $800 on November 14. How much is the accrued interest on December 31 if the rate of interest was 8% on May 8, 8.4% effective August 1, and 8.7% 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.)