I am looking to check myself on the following accounting examples:

Periodic Inventory by Three Methods; Cost of Merchandise Sold The units of an item available for sale during the year were as follows: Jan. 1 Inventory 40 units @ $92 Mar. 10 Purchase 70 units @ $102 Aug. 30 Purchase 20 units @ $110 Dec. 12 Purchase 70 units @ $112 There are 80 units of the item in the physical inventory at December 31. The periodic inventory system is used. Determine the inventory cost and the cost of merchandise sold by three methods. Round interim calculations to one decimal and final answers to the nearest whole dollar. Cost of Merchandise Inventory and Cost of Merchandise Sold Inventory Method Merchandise Inventory Merchandise Sold First-in, first-out (FIFO) $ Last-in, first-out (LIFO) Weighted average cost Performance Bike Co. is a wholesaler of motorcycle supplies. An aging of the company's accounts receivable on December 31 and a historical analysis of the percentage of uncollectible accounts in each age category are as follows: Estimate what the proper balance of the allowance for doubtful accounts should be as of December 31. Performance Bike Co. Estimation of Uncollectible Accounts December 31 Balance Estimated Uncollectible Accounts Percent Estimated Uncollectible Accounts Amount $510,000 1/2% Age Interval Not past due 1-30 days past due 31-60 days past due 61-90 days past due 91-180 days past due Over 180 days past due 56,100 25,500 18,400 13,300 9,700 Total $633,000 Effect of Doubtful Accounts on Net Income During its first year of operations, Mack's Plumbing Supply Co. had sales of $300,000, wrote off $4,800 of accounts as uncollectible using the direct write-off method, and reported net income of $33,000. Determine what the net income would have been if the allowance method had been used, and the company estimated that 1 3/4% of sales would be uncollectible. $