Assume that the overhead cost above consists of utilities, supervisory salaries, depreciation, and maintenance. The breakdown of these costs at the 80,000-machine-hour level of activity in October is as follows: ltiiestvaridie). ........................... mum WW5?!\" and mm (Md) .................. mill] mama) ....................... m Total warhmd cost ......................... W The company wants to break down the maintenance cost into its variable and xed cost elements. Required: 1. Estimate how much of the $483,200 of overhead cost in December was maintenance cost. (Hint: To do this, first determine how much of the $483,200 consisted of utilities and supervisory salaries. Think about the behaviour of variable and fixed costs within the relevant range.) 2. Using the highlow method, estimate a cost formula for maintenance. 3. Express the company's total overhead cost in the form Y = a + MI. 4. What total overhead cost would you expect to be incurred at an activity level of 90,000 machine-hours