The following merchandise transactions occurred during December for two different companies: Rippen and Burnen. Both companies use a perpetual inventory system. On December 3, Rippen Corporation sold merchandise on account to Burnen Corp. for $480,000, terms 2/10, n/30. This merchandise originally cost Rippen $320,000. On December 8, Burnen Corp. returned merchandise to Rippen Corporation for a credit of $30,000. Rippen returned this merchandise to inventory at its original cost of $20,000. December 12, Burnen Corp. paid Rippen Corporation for the amount owed. Required: a. Prepare the journal entries to record these transactions on the books of Rippen Corporation. (If no entry is required for a transaction/event, select "No Journal Entry Required" in the first account field.)