Assume that the overhead cost above consists of utilities, supervisory salaries, and maintenance. The breakdown of these costs at the 60,000-machine-hour level of activity in May is as follows: The company wants to break down the maintenance cost into its variable and fixed cost elements. 3. Express the company's total overhead cost in the form Y=a+bX. (Round the "Variable cost per unit" to 2 decimal places.) 7. What total overhead cost would you expect to be incurred at an activity level of 75,000 machine-hours? (Round the "Variable cost ber unit" to 2 decimal places.)