Determine the amount to be added to Allowance for Doubtful Accounts in each of the following cases and indicate the ending balance in each case.

a$.$ Credit balance of $$300$ in Allowance for Doubtful Accounts just prior to adjustment. Analysis of Accounts Receivable indicates uncollectible receivables of $$8,240.$

Amount added

Ending balance

$

b$.$ Credit balance of $$300$ in Allowance for Doubtful Accounts just prior to adjustment. Uncollectible receivables are estimated at $3\%$ of credit sales, which totaled $$1,011,000$ for the year.

Amount added

$

Ending balance

$