
Answer and Explanation:
According to the scenario,journal entry of the given data are as follow:-
Journal Entry
30 Sept   Cash A/c Dr. $21,800
        To Sales A/c  $20,000
 To Sales tax payable A/c $1,800      (20,000 × 9%)
         ( Being cash sales is recorded)
30 Sept  Cost of goods sold A/c Dr. $12,000
 To Inventory A/c $12,000
        ( Being September 30th sale cost is recorded)
15 Oct  Sales tax payable A/c Dr. $1,800
   To Cash A/c  $1,800
     ( Being payment of tax is recorded)