Answer:
                                         Dr.                  Cr.
Sale
Account Receivable    $300,000
Inventory                                          $210,000
Deffered Gross Profit                      $90,000
Payment Receipt
Cash                             $135,000
Account Receivable                        $135,000
Profit Recognition
Deffered Gross Profit  $40,500
Relaized Gross Profit                      $40,500
Explanation:
On sale a receivable is recorded and goods has been transferred to customer and its cost is been deducted from inventory. The Gross profit is deferred until the receipt of payment.
Deferred Profit = $300,000 x 30% = $90,000
Inventory cost = $300,000 - $90,000 = $210,000
Cash received from the customer, profit proportionated to the the cash receipt is realized gross profit.
Realized Profit = $135,000 x 30% = $40,500