37 Kimbeth Manufacturing uses a process cost system to manufacture Dust Density Sensors for the mining industry. The following information pertains to operations for the month of May: Units Beginning work-in-process inventory, May 1 16,000 Started in production during May 100,000 Completed production during May 92,000 Ending work-in-process inventory, May 31 24,000 The beginning inventory was 60 percent complete for materials and 20 percent complete for conversion costs. The ending inventory was 90 percent complete for materials and 40 percent complete for conversion costs. Costs pertaining to the month of May are as follows: Beginning inventory costs are: materials, $54,560; direct labor $20,320; and factory overhead, $15,240. Costs incurred during May are: materials used, S468,000; direct labor, $182,880; and factory overhead, $391,160. Using the first-in, first-out (FIFO) method, the equivalent units of production for materials are: 104,000 units. 107,200 units. 108,000 units. 113,600 units