Please explain the equations.

Sunland Company had 100 units in beginning inventory at a total cost of $10,000. The company purchased 300 units at a total cost of $42,000. At the end of the year, Sunland had 85 units in ending inventory. (a) Your answer is partially correct. Compute the cost of the ending inventory and the cost of goods sold under FIFO, LIFO, and average-cost. (Round average-cost per unit and final answers to 0 decimal places, e.g. 1,250.) FIFO LIFO Average-cost $ 11900 $ The cost of the ending inventory The cost of goods sold $