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 72% complete. Beginning work-in-process inventory for the current month was 18,000 units, 90% complete. During the month, 63,000 units were started in process, and 58,500 of these units were completed. There were no lost or spoiled units. If the ending inventory was 67% complete, the total equivalent units for Material B for the month was:

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