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Nova Company's total overhead cost at various levels of activity are presented below: Total Machine-Overhead Month April May June July Cost $ 223,200 Hours 55,000 45,000 198,200 65,000 248,200 75,000 273,200 Assume that the total overhead cost above consists of utilities, supervisory salaries, and maintenance. The breakdown of these costs at the 45,000 machine-hour level of activity is: Utilities (variable) Supervisory salaries (fixed) Maintenance (mixed) Total overhead cost $63,000 69,000 66,200 $198,200 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 $273,200 of overhead cost in July was maintenance cost. (Hint: to do this, it may be helpful to first determine how much of the $273,200 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 50,000 machine-hours