Tesla Inc. sells two models of electric vehicles: Model S and Model 3. The selling price, variable cost per unit, and contribution margin per unit for each model are as follows:

Model	Selling Price per Unit ($)	Variable Cost per Unit ($)	Contribution Margin per Unit ($)
Model S	$80,000	$60,000
Model 3	$40,000	$30,000

Calculate the missing contribution margin per unit for each model.