Nova Company's total overhead cost at various levels of activity are presented below: Month April May June July Machine-Hours Total Overhead Cost 51,000 $ 190,100 41,000 $ 166,100 61,000 $ 214,100 71,000 $ 238,100 Assume that the total overhead cost above consists of utilities, supervisory salaries, and maintenance. The breakdown of these costs at the 41,000 machine-hour level of activity is: Utilities (variable) Supervisory salaries (fixed) Maintenance (mixed) Total overhead cost $ 53,300 50,000 62,800 $ 166,100 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 $238,100 of overhead cost in July was maintenance cost. (Hint: to do this, it may be helpful to first determine how much of the $238,100 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 46,000 machine-hours?