Answer:
The Journal entries to record the given transactions would be:
Account Title Debit Credit
(1) Uncollectible Accounts Expense 18,600
Allowance for Doubtful Accounts 18,600
($600 + $18,000)
(2) Allowance for Doubtful Accounts 350
Accounts Receivable—Fronk Co. 350
(3) Accounts Receivable—Fronk Co. 200
Allowance for Doubtful Accounts 200
Cash 200
Accounts Receivable—Fronk Co. 200
(4) Cash 400
Allowance for Doubtful Accounts* 200
Accounts Receivable—Dodger Co. 600
($600 - $400)*