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4. Petra Company was formed on December 1, 2019. The following information is available from Petra's inventory record for Product X. Units Unit Cost January 1, 2020 (beginning inventory) 2,400 $18.00 Purchases: January 5, 2020 3.900 $20.00 January 25, 2020 3,600 $21,00 February 16, 2020 1,500 $22.00 March 15, 2020 2.700 $23.00 A physical inventory on March 31, 2020, shows 3,000 units on hand. Instructions Prepare schedules to compute the ending inventory at March 31, 2020, under each of the following inventory methods (a) FIFO. (6 Points) (6) LIFO. (6 Points) (c) Weighted average (15 Points)