The Allowance for bad debt account had a balance of $19,200 at the beginning of the year and $24,400at the end of the year. During the year (including the year end adjustment), bad debts expense of $36,000 was recognized. Calculate the total amount of past due accounts receivable that were written off as uncollectible during the year. (hint: make a T-Account for the allowance for bad debts account, plug in the amounts that you know, and solve for the missing amount.)