The Mattress Finishing Company has the following information available regarding costs at various levels of monthly production: Production volume (units) 3,000 6,000 Direct materials $12,000 $24,000 Direct labor 9,000 18,000 Indirect materials 4,500 7,500 Supervisors salaries 8,000 8,000 Depreciation on plant and equipment 4,000 4,000 Maintenance 11,000 16,000 Utilities 4,500 6,500 Insurance on plant and equipment 750 750 Property taxes on plant and equipment 1,000 1,000 ______ ______ Total $54,750 $85,750 _______ ________ Classify each of the costs above as being variable, fixed, or mixed by writing the name of each cost under one of the following headings: Variable Costs Fixed Costs Mixed Costs