Cullumber Corporation manufactures a single product. Monthly production costs incurred in the manufacturing process are shown below for the production of 3,500 units. The utilities and maintenance costs are mixed costs. The fixed portions of these costs are $370 and $250, respectively. Production in Units 3,500 Production Costs Direct materials $7,665 Direct labour 15,015 Utilities 1.805 Property taxes 1,180 Indirect labour 4,585 Supervisory salaries 1.950