We are evaluating a project that costs $800,000, has an eight-year life, and has no salvage value. Assume that depreciation is straight-line to zero over the life of the project. Sales are projected at 60,000 units per year. Price per unit is $40, variable cost per unit is $21, and fixed costs are $800,000 per year. The tax rate is 21 percent, and we require a return of 10 percent on this project.

b-2. What is the sensitivity of NPV to changes in the sales figure?