In the Coronado, maintenance costs are a mixed cost. At the low level of activity (100 direct labor hours), maintenance costs are $1200. At the high level of activity (500 direct labor hours), maintenance costs are $2750. Using the high-low method, what is the variable maintenance cost per unit and the total fixed maintenance cost? $5.50 $3.88 $5.50 $3.88 $275 $1550 $3250 $812