Nova Company's total overhead cost at various levels of activity are presented below: Month Machine-Hours Total Overhead Cost ril May June July 50,000 40,000 60,000 70,000 $183,600 $161,000 $206,200 $228,800 Assume that the total overhead cost above consists of utilities, supervisory salaries, and maintenance. The breakdown of these costs at the 40,000 machine-hour level of activity is Utilities (variable) Supervisory salaries (fixed) Maintenance (mixed) $ 48,000 57,000 56,000 Total overhead cost $161,000 Nova Company's management wants to break down the maintenance cost into its variable and fixed cost elements