help filling blanks using excel formulas

On December 31,20XX, the following information has been taken and summarized from the subsidiary accounts receivable ledger. The credit department believes that the uncollectable amounts can be determined with age using the following parameters: Required: Create an Aging of Accounts Receivable schedule. Determine the amount to use to adjust the Allowance for Doubtful Accounts account. Note: List the account names in atphabebical order. Sum the amounts in the "Amount Owed" column with the Aging Schedule, not the Subsidiary Ledger