I don't understand how to get the right answer. If someone can show how to get the right answer step by step in the style of the second screenshot, I would greatly appreciate it.

Use the following information to answer the following question. The Boxwood Company sells blankets for $60 each. The following was taken from the inventory records during May. The company had no beginning inventory on May 1. Date Product Z Units Cost per unit May 3 Purchase 5 $20 May 10 Sale 3 May 17 Purchase 10 $24 May 20 Sale 6 Assuming that the company uses the perpetual inventory system, determine the total cost of goods sold for the month of May using the LIFO inventory cost method. x $144 $540 $196 $204