Nova Company's total overhead cost at various levels of activity are presented below: Total Machine-Overhead Month April May June July Hours 49,000 39,000 59,000 69,000 224,290 Cost 178,090 $ 154,990 $ 201,190 Assume that the total overhead cost above consists of utilities, supervisory salaries, and maintenance. The breakdown of these costs at the 39,000 machine-hour level of activity is Utilities (variable) Supervisory salaries (fixed) Maintenance (mixed) Total overhead cost 42,900 46,000 66,090 $154,990 Nova Company's management wants to break down the maintenance cost into its variable and fixed cost elements