I a struggling with a case in the corporate finance book. Below is the case and the questions. I am struggling with the formulas used to calculate the answers.

Conch Republic spent $750.000 to develop a prototype for a new smart phone that has all the features of the existing one but adds new features such as wifi tethering. the company has spent a further $200,000 for a marketing study to determine the expected sales figures for the new smart phone.

Conch Republic can manufacture the new smart phone for $205 each in variable ccosts. Fixed costs for the operation are estimated to run $5.1 million per year. The estimated sales volume is 64,000, 106,000, 87,000, 78,000, 54,000 per year for the nest five years, respectively. The unit price of the new smart phone will be $485. The necessary equipment can be purchased for $34.5 million and will be depreciated on a seven-year MACRS schedule. It is believed the value of the equipment in five years will be $5.5 million.

Net working capital for the smart phones will be 20 percent of sales and will occur with the timing of the cash flows for the year(i.e., there is not initial outlay for NWC). Changes in NWC will thus first occur in Year 1 with the first year's sales. Conch Republic has a 35 percent corporate tax rate and a required return of 12 percent.

Prepare a report that answers the following questions:

What is the payback period of the project? What is the profitability index of the project? What is the IRR of the project? What is the NPV of the project?