help solve these

A company purchased 500 units for $60 each on January 31. It purchased 250 units for $30 each on February 28 It sold a total of 250 units for $70 each from March 1 through December 31 . If the company uses the weighted-average inventory costing method, calculate the cost of ending inventory on December 31. (Assume that the company uses a perpetual inventory system. Round any intermediate calculations two decimal places, and your final answer to the nearest dollar.) A. $37,500 B. $22,500 C. $12.500 D. $25,000 Using the perpetual inventory system, what is the amount of ending merchandise inventory? A. $144 B. $360 C. $18 D. $216