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Assume the Midwest Furniture Company sells two kinds of picnic tables, pine and redwood. At a 3:1 unit sales mix in which Midwest sells three pine tables for every redwood table, the following revenue and cost information is available. Pine Table Unit selling price Unit variable costs Unit contribution margin $200 $125 $75 Redwood Table $600 $ 275 $ 325 Fixed costs per month: $18,150 Required: Assuming a 3:1 sales mix: a) Calculate Midwest Furniture's current monthly average unit contribution margin. b) Break-even sales volume. c) Number of units of Pine and Redwood tables at break-even point. d) Describe what the effect a change in the sales-mix would have on contribution margin