E20-23 Determining mixed costs-the high- low method Learning Objective 1 $4,000 The manager of Trusty Car Inspection reviewed the monthly operating costs for the past year. The costs ranged from $4,300 for 1,300 inspections to $3,900 for 900 inspections. Requirements 1. Use the high-low method to calculate the variable cost per inspection. 2. Calculate the total fixed costs. 3. Write the equation and calculate the operating costs for 1,000 inspections