Russell Company's production and total cost data for two recent months follow:
January February
Units produced..............................................1,000.........................500
Total depreciation cost....................................$6,000.....................$6,000
Total factory supplies cost...............................$2,000.....................$1,000
Required
a. Separately calculate the depreciation cost per unit and the factory supplies cost per unit for both January and February.
b. Identify which cost is variable and which is fixed. Explain your answer.