Henry’s Helpers provides locksmith services. One type of service call is to evaluate private residences for security concerns and make recommendations for a safety plan. Use the data below to determine the company’s total contribution margin, contribution margin per service call, and contribution margin ratio when 220 service calls are made in the month of June. 

Service Revenue................................................... $ 170 per service call 

Variable Costs ............................................................68 per service call 

Fixed Costs................................................................ 21,040 per month