Final answer:
The accrued interest on December 31 is $442.60.
Step-by-step explanation:
Dirk Ward borrowed $13,000.00 on a demand note with a variable interest rate. To calculate the accrued interest on December 31, we need to consider the payments made and the changing interest rates. From May 5 to August 1, the interest rate is 8%, so we calculate the interest on the outstanding balance of $13,000.00. Then, from August 1 to November 1, the rate is 8.25%, and finally, from November 1 to December 31, it's 8.6%. The payments made on June 26, September 21, and November 7 are subtracted from the interest accrued during their respective periods.
To break it down:
1. May 5 to June 26 (8%): $13,000.00 * (8% / 12) * 52/365 = $86.30
2. June 26 to September 21 (8%): $12,199.50 * (8% / 12) * 87/365 = $252.04
3. September 21 to November 1 (8.25%): $11,947.46 * (8.25% / 12) * 41/365 = $75.45
4. November 1 to December 31 (8.6%): $11,872.01 * (8.6% / 12) * 61/365 = $116.81
Adding these values gives the total accrued interest on December 31: $86.30 + $252.04 + $75.45 + $116.81 = $530.60. Subtracting the payments made: $530.60 - $800 - $150 - $1000 = -$419.40. Since the result is negative, it means Dirk overpaid by $419.40. Adding this overpayment to the initial accrued interest gives the final answer: $530.60 - $419.40 = $442.60.