E21-12 Silicon Semiconductors, Inc., experienced the following activity in its Photolith- ography Department during December. Materials are added at the beginning of the photolith- ography process. Units: Work in process, November 30 (80% of the way through the process).. Transferred in from the Polishing and Cutting Department during December. Completed during December Work in process. December 31 (70% of the way through the process) Costs: Work in process, November 30. Transferred in from the Polishing and Cutting Department during December. Conversion costs added during December. Direct materials added during December. 8,000 units 27,000 units 26,000 units 9,000 units $60,116 97.200 74,250 90,650 Required 1. Draw a time line for the Photolithography Department using the FIFO method. (See Exhibit 21-11.) 2. Use the time line to help you compute the number of equivalent units of work performed by the Photolithography Department during December. Use the FIFO method. 3. Compute the costs per equivalent unit, and assign total cost to

(a) units completed and transferred to Finished Goods Inventory, and

(b) units in December 31 work in process inventory.