At the end of the current year, the accounts receivable account has a balance of $200,000 and net sales for the year total $1,000,000.

Determine the amount of the adjusting entry to provide for doubtful accounts under each of the following assumptions:

a. The allowance account before adjustment has a negative balance of $20,000. Bad debt expense is estimated at 1% of net sales.

b. The allowance account before adjustment has a negative balance of $2,000. An aging of the accounts in the customer ledger indicates estimated doubtful accounts of $20,000.

c. The allowance account before adjustment has a positive balance of $38,000. Bad debt expense is estimated at 2% of net sales.

d. The allowance account before adjustment has a positive balance of $3,800. An aging of the accounts in the customer ledger indicates estimated doubtful accounts of $10,000