Mel owns a machine shop. In reviewing the shop's utility bills for the past $12$ months, he found that the highest bill of $$2,700$ occurred in August when the machines worked $1,300$ machine hours. The lowest utility bill of $$2,500$ occurred in December when the machines worked $800$ machine hours.

Read the requirements.

Requirement $1.$ Use the high$-$low method to calculate the variable cost per machine hour and the total fixed utility cost.

First, calculate the variable cost per machine hour. Select the formula labels, then enter the amounts and compute the variable cost per machine hour. $($Use the high$-$low method. Round your answer to the nearest cent.$)$

$=$ Variable cost per machine hour