The controller of Pharoah Industries has collected the following monthly expense data for use in analyzing the cost behavior of maintenance costs. Month January February March April May June (a1) Total Maintenance Costs $2,620 2,920 3,520 4,420 3.120 5,220 Total Machine Hours 310 360 510 680 510 710 Determine the variable cost components using the high-low method. (Round answer to 2 decimal places e.g. 2.25.) Variable cost per machine hour $