Betty Harris owns and operates Cullumber, a bakery that creates personalized birthday cakes for a child's first birthday. The cakes, which sell for $65 and feature an edible picture of the child, are shipped throughout the country. A typical month's results are as follows: $962,000 577,200 Sales revenue Variable expenses Contribution margin Fixed expenses Operating income 384,800 211.640 $ 173,160 (a) What is Cullumber's contribution margin per unit? Contribution margin per unit per cake