Beech Company produces a single product. The company has $40,000$ units in its beginning inventory. Beech's variable production costs during the year were $$10$ per unit and fixed manufacturing overhead costs were applied at $$30$ per unit $($which was the same as last year$).$ The company's net operating income is $$102,000$ lower under variable costing than it is under absorption costing; and the company uses FIFO and closes any over$-$ or under$-$applied overhead directly to cost of goods sold. Given these facts, what was the number of units of product in ending inventory?