Assume that on September 1 Office Depot had an inventory that included a variety of calculators. The company uses a perpetual inventory system. During September these transactions occurred. Sept. 6 Purchased calculators from Green Box Co. at a total cost of $1,620, terms n/30. 9 Paid freight of $50 on calculators purchased from Green Box Co. 10 Returned calculators to Green Box Co. for $38 credit because they did not meet specifications. 12 Sold calculators costing $520 for $690 to University Book Store, terms n/30. 14 Granted credit of $45 to University Book Store for the return of one calculator that was not ordered. The calculator cost $34. 20 Sold calculators costing $570 for $760 to Campus Card Shop, terms n/30