Department A had 4,700 units in work in process that were 71% completed as to labor and overhead at the beginning of the per o 2 80 units of ect materials ere added during the period; 31,500 units were completed during the period; and 3,000 units were 31% completed as to labor and overhead at the end of the period. All materials are added at the beginning of the process. The first-in, first-out method is used to cost inventories. The number of equivalent units of production for material costs for the period was . 31,500 Ob. 26,800 CC. 34,500 Od. 29,800