On October 5, Riverbed Corporation buys merchandise for resale on account from Concord Corporation. The selling price of the goods is $5,380, and the cost to Concord Company is $2,940. On October 8 , Riverbed returns defective goods with a selling price of $750 and a cost of $270. It is anticipated that these goods can be resold at a discount at some point in the future for at least their cost of $270, if not more. Both companies use a periodic inventory system. (a) Record the transactions on the books of Riverbed Corporation. (Credit account titles are automatically indented when the amount is entered. Do not indent manually. If no entry is required, select "No Entry" for the account titles and enter of for the amounts.)