Wildhorse Industries manufactures and sells three different models of wet-dry shop vacuum cleaners. Although the shop vacs vary in terms of quality and features, all are good sellers. Wildhorse is currently operating at full capacity with limited machine time. Per unit sales and production information relevant to each model follows. Product Economy Standard Deluxe Selling price $39 $66 $131 Variable costs and expenses $21 $26 $61 Machine hours required 0.50 0.80 1.60 (a1) Calculate unit contribution margin. Unit contribution margin Product Economy Standard Deluxe