Aria Acoustics, Inc. (AAI), projects unit sales for a new seven-octave voice emulation implant as follows: Year Unit Sales 1 71,500 2 87,800 3 104,300 4 89,200 5 75,300 Production of the implants will require $1.5 million in net working capital to start and additional net working capital investments each year equal to 15 percent of the projected sales increase for the following year. Total fixed costs are $2.15 million per year, variable production costs are $230 per unit, and the units are priced at $375 each. The equipment needed to begin production has an installed cost of $20.5 million. Because the implants are intended for professional singers, this equipment is considered industrial machinery and thus qualifies as seven-year MACRS (MACRS Table) property. In five years, this equipment can be sold for about 20 percent of its acquisition cost. AAI has a 21 percent tax rate and a required return on all its projects of 15 percent. a. What is the NPV of the project? (Do not round intermediate calculations and round your answer to 2 decimal places, e.g., 32.16.) b. What is the IRR? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.)

I just want to ask how to calculate the NWC(especially the 5th year's)