HammerTime makes high quality tools. The company controller want to calculate the fixed and variable costs associated with the janitorial costs incurred in the production factory. Data for the past four months were collected as follows:

Janitorial Costs Machine Hours

Month:

September $ $12700760$

October $11,000550$

November $8600400$

December $11,700600$

Using the high$-$low method, calculate the variable cost per unit of the janitorial services.