with formla or rules

We are evaluating a project that costs $854,000, has a 15 -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 154,000 units per year. Price per unit is $41, variable cost per unit is $20, and fixed costs are $865,102 per year. The tax rate is 33 percent, and we require a 14 percent return on this project. Suppose the projections given for price, quantity, variabie costs, and fixed costs are all accurate to within \pm 14 percent. What is the worst-case NPV