Mark owns a machine shop. In reviewing the shop’s utility bills for the past 12 months, he found that the highest bill of $2,400 occurred in August when the machines worked 1,000 machine hours. The lowest utility bill of $2,200 occurred in December when the machines worked 500 machine hours.

Requirements 1. Calculate the variable rate per machine hour and the total fixed utility cost.

2. Show the equation for determining the total utility cost for the machine shop.

3. If Mark anticipates using 700 machine hours in January, predict the shop’s total utility bill using the equation from Requirement 2.