On September 1, the beginning of its fiscal year, Campus Office Supply Ltd. had an inventory of 126 calculators at a cost of 520 each. The company uses a perpetual inventory system. During September, the following transactions occurred: Sept. 2. Purchased 945 calculators for $20 each from Digital Corp. on account, terms n/30. 10 Returned 31 calculators to Digital for $620 credit because they did not meet specifications. 11 Sold 440 calculators for $30 each to Campus Book Store, terms r/30. Management estimates returns of 4% based on prior experience. 14. Granted credit of $930 to Campur Book Store for the return of 31 calculators that were not ordered. The calculators were restored to inventory. 29. Paid Digital the amount owing 30 Recelved payment in full from the Campus Book Store