Mark Corporation produces two models of calculators. The Business model sells for $50, and the Math model sells for $30. The variable expenses are given below:

Business

ModelMath

Model Variable production costs per unit$20 $21 Variable selling and administrative expenses per unit$ 5 $ 2 The fixed expenses are $74,000 per month. The expected monthly sales of each model are: Business, 2,100 units; Math, 1,600 units.

The contribution margin ratio for the Business model is: (Do not round intermediate calculations.)60%

30%

50%

70%