Crosshill Companys total overhead costs at various levels of activity are presented below:

Month	Machine-Hours	Total Overhead Cost
April	70,000	$	202,200
May	60,000	$	180,300
June	80,000	$	224,100
July	90,000	$	246,000

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:

Utilities (variable)	$	52,200
Supervisory salaries (fixed)		21,000
Maintenance (mixed)		107,100
Total overhead cost	$	180,300

The company wants to break down the maintenance cost into its variable and fixed cost elements.

Required:

1. Estimate how much of the $246,000 of overhead cost in July was maintenance cost. (Hint:To do this, first determine how much of the $246,000 consisted of utilities and supervisory salaries. Think about the behaviour of variable and fixed costs within the relevant range.) (Round the "Variable cost per unit" to 2 decimal places.)

2. Using the highlow method, estimate a cost formula for maintenance. (Round the "Variable cost per unit" to 2 decimal places.)

3. Express the companys total overhead cost in the form Y = a + bX. (Round the "Variable cost per unit" to 2 decimal places.)

4. What total overhead cost would you expect to be incurred at an activity level of 75,000 machine-hours? (Round the "Variable cost per unit" to 2 decimal places.)