I need help solving this please

Ledo Inc. had a 1/1/18 balance in the Allowance for Doubtful Accounts of $20,000. During 2018, it wrote off $12, 600 of accounts and collected $3, 200 on accounts previously written off. The balance in Accounts Receivable was $400,000 at 1/1 and $485,000 at 12/31. At 12/31/18, Smithson estimates that 8% of accounts receivable will prove to be uncollectible. What is Bad Debt Expense for 2018