Question 7: Lith Co. began operation on July 1, using a perpetual inventory system. During July, the company had the following purchases and sales: Date July 1 July 6, sale July 11, purchase July 14, sale July 21, purchase July 27, sale Quantity Unit cost Unit sale 5 122 2 Y1 7 136 6 Y2 8 147 8 Y3 Require: Give Y1, Y2, Y3 by yourself Determine cost of goods sold, the ending inventory, gross profit under perpectual and periodic inventory system using FIFO, average cost method