On September 1, Boylan Office Supply had an inventory of 30 calculators at a cost of $18 each. The company uses a perpetual inventory system. During September, the following transactions occurred. Sept. 6 purchased with cash 80 calculators at $20 each from Guthrie Co Sept. 9 Paid freight of $80 on calculators purchased from Guthrie Co. Sept. 10 Returned 3 calculators to Guthrie Co. for $63 cash (including freight) because they did not meet specifications. Sept. 12 Sold 26 calculators costing $21 (including freight) for $31 each to Lee Book Store, terms n/30. Sept. 14 Granted credit of $31 to Lee Book Store for the return of one calculator that was not ordered. Sept. 20 Sold 30 calculators costing $21 for $32 each to Orr's Card Shop, terms n/30