Please tell me how to get these numbers?

At the end of the current year (before adjusting entries), Autumn Corporation had a balance of $76,000 in Accounts Receivable and a credit balance of $11,000 in Allowance for Uncollectible Accounts. Service revenue (all on credit) for the year totaled $490,000.

Requirement 1. Using the percent-of-sales method, calculate the amount of Uncollectible-Account Expense if Autumn Corporation estimates its uncollectible-account expense using a rate of

22% of credit sales. What is the ending balance of the Allowance for Uncollectible Accounts under this scenario?

Autumn Corporation has $	9,800	of uncollectible-account expense using the percent-of-sales method. The ending
balance of the Allowance for Uncollectible Accounts is $			20,800	under this scenario.

Requirement 2. Now assume that Autumn Corporation uses the aging-of-receivables method. Autumn

Corporation estimates that its Allowance for Uncollectible Accounts should have a credit balance of

$21,000. Calculate the amount of its Uncollectible-Account Expense. What is the ending balance of the Allowance for Uncollectible Accounts under this scenario?

Autumn Corporation has $	10,000	of uncollectible-account expense using the aging-of-receivables method. The ending
balance of the Allowance for Uncollectible Accounts is $			21,000	under this scenario.