i can't understand how did my instructor got those numbers?

can i get a clear step by step on how to get the results ( for Weight average, LIFO and FIFO)

thanks

Part 1: Information relating to the inventory quantities, purchases and sales of an eight inch ( 8) speaker unit by the Stereo Company during 2022 is shown below: INSTRUCTIONS: Show all final answers in the Answer Grid below a. Compute the cost of the December 31,202 inventory and the cost of goods sold for the units in 2022 using: 1. Weighted Average 2. LIFO 3. FIFO b. In February of 2023, Stereo Company purchased 1000 units at 31.20 per unit, and then in March of 2023 they sedd 2000 units. What is the cost of goods sold for the 2000 units sold in March, 2023 under each of the three methods? There is space on page 3 for your calculations b. In February of 2023 , Stereo Company purchased 1000 units at 31.20 per unit, and then in March of 2023 they setd 2000 units. What is the cost of goods sold for the 2000 units sold in March, 2023 under each of the three methods? There is space on page 3 for your calculations >>>