Nova Companys total overhead cost at various levels of activity are presented below: Month Machine- Hours Total Overhead Cost April 48,000 $ 185,800 May 38,000 $ 161,800 June 58,000 $ 209,800 July 68,000 $ 233,800 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) 58,000 Maintenance (mixed) 58,200 Total overhead cost $ 161,800 Nova Companys management wants to break down the maintenance cost into its variable and fixed cost elements. Required: 1. Estimate how much of the $233,800 of overhead cost in July was maintenance cost. (Hint: to do this, it may be helpful to first determine how much of the $233,800 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?