This is my question

A first-in, first-out (FIFO) process cost system is used to account for the cost of producing a chemical compound. As part of production, Material B is added when the goods are 48% complete. Beginning work-in-process inventory for the current month was 12,000 units, 60% complete. During the month, 42,000 units were started in process, and 39,000 of these units were completed. There were no lost or spoiled units. If the ending inventory was 43% complete, the total equivalent units for Material B for the month was: