Answer:
1. Journal entry for the sales of merchandise
General Journal Entry
Date Account Titles and Explanation Debit Credit
Sept 30 Cash ($6000 + $300) $6,300
Sales $6,000
Sales Tax Payable($6000 * 5%) $300
(To record the collection of sales and sales tax)
2. Journal entry for the cost of merchandise sold
General Journal Entry
Date Account Titles and Explanation Debit Credit
Sept 30. Cost of goods sold $3,900
Merchandise inventory $3,900
(To record the cost of merchandise sold by receiving cash)
3. Journal entry for the cost of merchandise sold
General Journal Entry
Date Account Titles and Explanation Debit Credit
Oct 15. Sales Tax payable $300
Cash $300
(To record the payment of accrued sales tax to government)