The following is information concerning a product manufactured by Ames Brothers: Sales price per unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $ 24 Variable cost per unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Total fixed manufacturing and operating costs (per month) . . . . . . . . . . . . . . . . . . . 405,000 Determine the following: a. The unit contribution margin. b. The number of units that must be sold each month to break even and break even sales in dollars. c. The unit sales level that must be reached to earn an operating income of $270,000 per month. d. Operating income if annual sales total 60,000 units.