In September, Cullumber Industries sold 800 units of product. The average sales price was $45. During the month, fixed costs were $6,615 and variable costs were 75% of sales. (a) Determine the contribution margin in dollars, per unit, and as a ratio. (Round Contribution margin to 0 decimal places, e.g. 5,275. Other all answers to 2 decimal places, e.s. 52.75.) Contribution margin (in dollars) $ Unit contribution margin Contributionmargin ratio