3-M:5-23 Determining mixed costs - the high-low method 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. 4. Draw a graph illustrating the total cost under this plan. Label the axes, and show the costs at 900,1,000, and 1,300 inspections