at the end of 2020 a firm had accounts receivable of $251,000 and allowance fir bad debt of $22,000. during 2020 credit sales were 960,000 and cash collected from customers was 891,000. at the begining of 2020 accounts receivable was 213,000 and allowance of bad debts was 29,000 calculate the amount of account receivable that was written off during 2020