Calculate the weighted-average unit cost. (Round answer to 3 decimal places, e.g. 5.125.) Weighted-average unit cost $ 10.087 (b) Calculate the ending inventory at May 31 using the FIFO, LIFO and average-cost methods. (Round answers to 0 decimal places, e.g. 125.) Calculate the weighted-average unit cost. (Round answer to 3 decimal places, e.g. 5.125.) Weighted-average unit cost $ 10.087 (b) Calculate the ending inventory at May 31 using the FIFO, LIFO and average-cost methods. (Round answers to 0 decimal places, e.g. 125.)