Elm uses the high-low method of estimating costs. Elm had total costs of $247,750 at its lowest level of activity, when 10,900 units were sold. When, at its highest level of activity, sales equaled 16,600 units, total costs were $398,800. Elm would estimate variable cost per unit as: Multiple Choice O $22.73 $23.51 O $26.50 O $24.02