The following are selected transactions and other data of the Custer Company: Purchased 20 units at $ 360 per unit on account on 2010 September 18. Sold 6 units on account for $ 576 per unit on 2010 September 20. Discovered a shortage of $ 2,640 at year-end after a physical inventory. Prepare journal entries for these transactions using FIFO perpetual inventory procedure. Assume the beginning inventory consists of 20 units at $ 336 per unit