On September 15, Krug Company purchased merchandise inventory from Makarov with an invoice price of $35,000 and credit terms of 2/10, n/30. Krug Company paid Makarov on September 28. Prepare any required journal entry(ies) for Krug Company (the purchaser) on: (a) September 15, and (b) September 28. Assume Krug uses the perpetual inventory method.