I'm needing help with best and worst case NPV. thanks in advance.

You are considering a new product launch. The project will cost $870,000, have a 4-year life, and have no salvage value; depreciation is straight-line to zero. Sales are projected at 530 units per year, price per unit will be $18,900, variable cost per unit will be $15,600, and fixed costs will be $905,000 per year. The required return on the project is 14 percent, and the relevant tax rate is 25 percent. a. The unit sales, variable cost, and fixed cost projections given above are probably accurate to within 10 percent. What are the upper and lower bounds for these projections? What is the base-case NPV? What are the best-case and worst-case scenarios? (A negative amount should be indicated by a minus sign. Do not round intermediate calculations and round your NPV answers to 2 decimal places, e.g., 32.16.) Answer is complete and correct. Scenario Unit sales Variable cost per unit Fixed costs Upper bound Lower bound 583 477 units $ 17,160S 14.040 $ 995,500 $ 814,500 Answer is not complete. Scenario NPV Base-case $ 1,132,813.00 Best-case Worst-case