I am having troubles figuring this out, could you help. thanks.

Unadjusted Trial Balance at year-end included the following accounts:

DebitCreditSales (75% represent credit sales)$1,152,000Accounts Receivable$288,000Allowance for Doubtful Accounts$2,184

Compute the uncollectible account expense, and make the appropriate journal entry, for the current year assuming the uncollectible account expense is determined as follows:

• a. Without considering the balance in the Allowance for Doubtful Accounts, income statement approach, 1% of total sales.
• b. Without considering the balance in the Allowance for Doubtful Accounts, income statement approach, 1.5% of credit sales.
• c. Considering the balance in the Allowance for Doubtful Accounts, balance sheet approach. The estimate based on an aging of accounts receivable is that an allowance of $12,000 would be appropriate.

If I did this correct my answers are:

a. $11,520

b. $12,960

c. $9,816