Adams Corporation uses a periodic inventory system and the retail inventory method to estimate ending inventory and cost of goods sold. The following data are available for the month of September 2016: Cost Retail Beginning inventory $ 21,800 $ 38,200 Net purchases 10,900 ? Net markups 8,000 Net markdowns 2,000 Net sales ? The company used the average cost flow method and estimated inventory at the end of September to be $17,494.50. If the company had used the LIFO cost flow method, the cost-to-retail percentage would have been 50%. Required: Compute net purchases at retail and net sales for the month of September.