On September 1, Blue Spruce Inc. had an inventory of 42 backpacks at a cost of $30 each. The company uses a perpetual inventory system and estimates returns at 10%. During September, the following transactions occurred: sep 4 Purchased 59 backpacks at $30 each from Back Packs Unlimited, terms n/30. Received credit of $240 for the return of 8 backpacks purchased on Sept. 4 that were defective. Sold 44 backpacks for $50 each to University Supply, terms n/30. 14 Paid