In the month of June, Oriole Hebert's Beauty Salon gave 4,500 haircuts, shampoos, and hair colorings at an average price of $40. During the month, fixed costs were $18,000 and variable costs were 75% of sales. (a) Determine the contribution margin in dollars, per unit and as a ratio. (Round contribution margin per unit to 2 decimal places, e.g. 5.75.) Contribution margin Unit contribution margin Contribution margin ratio