bad debt expense

how do i find the bad debt expense using these numbers ??

Use the information that follows taken from the unadjusted trial balance and aging schedule of Behrend Company on December 31, 2017 to answer the questions below. All sales are on account. Accounts and related balances at December 31, 2017 before adjustment: Debit Credit Accounts receivable $47,000 $420 Allowance for doubtful accounts Sales (all on account) 400,000 Sales returns 2,000 Aging Schedule of Accounts Receivable: % Uncollectible Age Amount 0-30 days $15,000 2% 30-60 days 18,000 7% Over 60 days 14,000 13% If Behrend uses the aging schedule of accounts receivable to determine bad debts, determine the following: (a) Bad debt expense for the year ending December 31, 2017. Bad debt expense $