The manager of Able Car Inspection reviewed his monthly operating costs for the past year. His costs ranged from $4,000 for 1,000 inspections to $ 3,600 for 600 inspections.

1. Calculate the variable cost per inspection.
2. Calculate the total fixed costs.
3. Write the equation and calculate the operating costs for 800 inspections.
4. Draw a graph illustration your total cost under this plan. Label the axes, and show your costs at 600, 800, and 1,000 inspections.