Dot and Ken Ice Cream uses a mixing department and a freezing department in producing its ice cream. Its process-costing system in the mixing department has two direct materials cost categories (ice cream mix and flavorings) and one conversion cost pool. The following data pertain to the mixing department for April 2017:

Work in process, April 1 0
Started in April 10,000 gallons
Completed and transferred to freezing 8,500 gallons
Costs:
Ice cream mix $27,000
Flavorings $4,080
Conversion costs $53,700

The ice cream mix is introduced at the start of operations in the mixing department, and the flavorings are added when the product is 40% complete in the mixing department. Conversion costs are added evenly during the process. The ending work in process in the mixing department is 30% complete. Dot Icecream uses a weighted-average process costing.
A. Calculate the equivalent units of work for the month of April for each cost category (i.c. the equivalent units of work for ice cream mix, flavorings, and conversion costs).
B. Calculate the cost of goods completed and transferred to the freezing department during April.
C. Briefly explain equivalent units and why they are necessary in process costing.