Nova Company's total overhead cost at various levels of activity are presented below Total Machine- Overhead Month Hours Cost April May $190,080 $167,480 $212,680 $ 235,280 53,000 43,000 63,000 June July 73,000 Assume that the total overhead cost above consists of utilities, supervisory salaries, and maintenance. The breakdown of these costs at the 43,000 machine-hour level of activity is: Utilities (variable) Supervisory salaries (fixed) Maintenance (mixed) 51,600 53,000 62,880 $167,480 Total overhead cost Nova Company's management wants to break down the maintenance cost into its variable and fixed cost elements. Required: 1. Estimate how much of the $235,280 of overhead cost in July was maintenance cost. (Hint: to do this, it may be helpful to first determine how much of the $235,280 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 company's 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 48,000 machine-hours