Answer:
Fraud Investigators Inc.
1. Journal Entries:
March 31:  Debit Accounts Receivable $21,000 
Credit Service Revenue $21,000
To record the rendering of service on account.
Oct. 31: Debit Allowance for Uncollectible Accounts $1,300 
Credit Accounts Receivable $1,300
To write-off uncollectible accounts.
Dec. 15: Debit Accounts Receivable $760 
Credit Allowance for Uncollectible Accounts $760
To reverse a previously written-off account.
Dec. 15: Debit Cash $760 
Credit Accounts Receivable $760
To record the cash collected from the customer.
Dec. 31: Debit Bad Debts Expense $460 
Credit Allowance for Uncollectible Accounts $460
To record bad debts expense for the year.
A) Debit Accounts Receivable $34,000 
Credit Service Revenue $34,000
To record the rendering of service on account.
B) Debit Allowance for Uncollectible Accounts $1,950 
Credit Accounts Receivable $1,950
To write off uncollectible accounts.
C1) Debit Accounts Receivable $810 
Credit Allowance for Uncollectible Accounts $810
To reverse a previously written-off debt.
C2) Debit Cash $810 
Credit Accounts Receivable $810
To record the receipt of cash from the customer.
D) Debit Bad Debts Expense $590 
Credit Allowance for Uncollectible Accounts $590
To record bad debts expense for the year.
2. Transaction  Net Receivable  Net Sales   Income From Operation
         A                  +34,000           +34,000           +34,000
         B                  -1,950                 NE                   -1950
         C                  +/- 810                NE                    +810
         D                   NE                     NE                    -590
Explanation:
a) Data and Analysis:
March 31:  Accounts Receivable $21,000 Service Revenue $21,000
Oct. 31: Allowance for Uncollectible Accounts $1,300 Accounts Receivable $1,300
Dec. 15: Accounts Receivable $760 Allowance for Uncollectible Accounts $760
Dec. 15: Cash $760 Accounts Receivable $760
Dec. 31: Bad Debts Expense $460 Allowance for Uncollectible Accounts $460
A) Accounts Receivable $34,000 Service Revenue $34,000
B) Allowance for Uncollectible Accounts $1,950 Accounts Receivable $1,950
C1) Accounts Receivable $810 Allowance for Uncollectible Accounts $810
C2) Cash $810 Accounts Receivable $810
D) Bad Debts Expense $590 Allowance for Uncollectible Accounts $590