Nike Inc. sells three types of shoes: Running, Basketball, and Casual. The selling price, variable cost per unit, and contribution margin per unit for each type are as follows:

Shoe Type	Selling Price per Unit ($)	Variable Cost per Unit ($)	Contribution Margin per Unit ($)
Running	$120	$80
Basketball	$150	$100
Casual	$90	$50

Calculate the missing contribution margin per unit for each shoe type.