Answer:
(a) On December 10, a customer balance of $1,400 from a prior year was determined to be uncollectible
Dr Sales Returns and Allowances $ 1,400  
Cr Accounts Receivable   $ 1,400
(b) On December 31, a decision was made to continue the accounting policy of basing estimated bad debt losses on 2 percent of credit sales for the year.
Dr Bad Debt Expense $ 752  
Cr Allowance for Uncollectible Accounts  $ 752
Explanation:
Initial Balance  
Dr Accounts Receivable   $ 12,000
Cr Allowance for Uncollectible Accounts  $ 500
Kelly’s Camera Shop had sales revenue, of which $60,000 was on credit  
Dr Accounts Receivable  $ 60,000  
Cr Sales  $ 60,000
Collections of accounts receivable during 2018 amounted to $58,000.  
Dr Cash $ 58,000  
Cr Accounts Receivable   $ 58,000
(a) On December 10, a customer balance of $1,400 from a prior year was
determined to be uncollectible, so it was written off.  
Dr Allowance for Uncollectible Accounts $ 1,400  
Cr Accounts Receivable   $ 1,400
(b) On December 31, a decision was made to continue the accounting policy of basing estimated bad debt losses on 2 percent of credit sales for the year.  
Dr Bad Debt Expense $ 752  
Cr Allowance for Uncollectible Accounts  $ 752