not sure what im doing wrong but when im calculating interest for april 15 to july 20 the interest is higher than the repayment. idk i got confused need detailed steps please thanks

9. Herb's Restaurant borrowed $24 000 on March 1 on a demand note provid. ing for a variable rate of interest. While repayment of principal is open , any accrued interest is to be paid on November 30. Payments on the loan were made as follows: $600 on April 15, $400 on July 20, and $400 on October 10. The rate of interest was 7% on March 1 but was changed to 8.5% effec- tive August 1 and to 7.5% effective November 1. Using the declining balance method to record the partial payments, determine the accrued interest on November 30