ABC Company's total overhead costs at various levels of activity are presented below:

Machine hours Total overhead costs

March $60,000$ $$216,800$

April $50,000194,000$

May $70,000239,600$

June $80,000262,400$

Assume that the overhead costs above consist of utilities, supervisory salaries, and maintenance. At the $50,000-$machine$-$hour level of activity, these costs are presented below:

Utilities $($V$)$ $$54,000$

Supervisory salaries $($F$)62,000$

Maintenance $($M$)78,000$

Total overhead costs $$194,000$

V $=$ Variable, F $=$ Fixed, M $=$ Mixed

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

Required:

a$)$ Estimate the maintenance cost for June.

b$)$ Use the high$-$low method to estimate the cost formula for maintenance cost.

c$)$ Estimate the total overhead cost at an activity level of $55,000$ machine hours, using the separate estimates you obtained for its components.

d$)$ Estimate the total overhead cost at an activity level of $55,000$ machine hours, independent of the separate estimates you obtained for its components.