Nova Companys total overhead cost at various levels of activity are presented below: Month Machine-Hours Total Overhead Cost April 48,000 $ 180,120 May 38,000 $ 157,220 June 58,000 $ 203,020 July 68,000 $ 225,920 Assume that the total overhead cost above consists of utilities, supervisory salaries, and maintenance. The breakdown of these costs at the 38,000 machine-hour level of activity is: Utilities (variable) $ 45,600 Supervisory salaries (fixed) 57,000 Maintenance (mixed) 54,620 Total overhead cost $ 157,220 Nova Companys management wants to break down the maintenance cost into its variable and fixed cost elements. Required: 1. Estimate how much of the $225,920 of overhead cost in July was maintenance cost. (Hint: to do this, it may be helpful to first determine how much of the $225,920 consisted of utilities and supervisory salaries. Think about the behavior of variable and fixed costs.) 2. Using the high-low method, estimate a cost formula for maintenance in the form Y = a + bX. 3. Express the companys total overhead cost in the form Y = a + bX. 4. What total overhead cost would you expect to be incurred at an activity level of 43,000 machine-hours