ZZ Tire Company opened a new location last year. Use the following information to figure out contribution margin and operating income for last year: Tires sold: 15,000 Retail Price per tire: $75 per tire Cost per tire: $18 per tire Installation expense per tire (payroll): $9 per tire Utilities: $2,000 per month Rent: $3,500 per month Clerks and phone receptionist: $2,500 per month