Weather Instruments assembles products from component parts. It has two departments that process all products, the Assembly Department and the Finishing Department, respectively. The process costing system with the FIFO cost flow assumption is being used. Summary data for January-Assembly Department WIP inventory, January 1 Degree of completion of beginning WIP Started during January Completed and transferred out during January WIP inventory, January 31 Degree of completion of ending WIP Units 20,000 DM Costs Conversion Costs $12,000 $4,000 100% 50% 40,000 50,000 8,000 100% 40% Required: Costs added during January: Direct materials, $44,000; Direct labor, $16,000. Overhead is applied at the rate of 50% of direct manufacturing labor costs. All spoilage is considered normal and is detected at the end of the process. (a) Explain equivalent units