3. Swifty Co. provides for doubtful accounts based on 3% of gross accounts receivable, The following data are available for 2020. Credit sales during 2020 $3,640,100 Bad debt expense 57,270 Allowance for doubtful accounts 1/1/20 16,110 Collection of accounts written off in prior years (customer credit was reestablished) 7,620 Customer accounts written off as uncollectible during 2020 31,280 What is the balance in Allowance for Doubtful Accounts at December 31, 2020