Nova Company's total overhead cost at various levels of activity are presented below: Total Machine-Overhead Month April May une July Hours 55,000 45,000 203,050 65,000 75,000 284,950 Cost 230,350 257,650 Assume that the total overhead cost above consists of utilities, supervisory salaries, and maintenance. The breakdown of these costs at the 45,000 machine-hour level of activity is: Utilities (variable) Supervisory salaries (fixed) Maintenance (mixed) Total overhead cost $67,500 61,000 74,550 $203,050 Nova Company's management wants to break down the maintenance cost into its variable and fixed cost elements