The following merchandise transactions occurred in December

The following merchandise transactions occurred in December. Both companies use a perpetual inventory system. 
Dec. 3 Riverbed Ltd. sold goods to Concord Corp. for $85.600, terms n/15, FOB shipping point. The inventory had cost Riverbed $45,600. Pictou's management expected a return rate of 3% based on prior experience. 7 Shipping costs of $1,200 were paid by the appropriate company. 8 Concord returned unwanted merchandise to Riverbed. The returned merchandise has a sales price of $2.640, and a cost of $1.400. It was restored to inventory. 11 Riverbed received the balance due from Concord.