Please explain why is the above formula is applied in the working? According to the below solution, it wrote that it is using both combination of interest rate parity(IRP) and purchase power parity(PPP) formula. How to get the above formula using IRP and PPP?

C12/Q14 Capital Budgeting Lakonishok Equipment has an investment opportunity in Europe. The project costs 19 million and is expected to produce cash flows of 3.6 million in Year 1,4.1 million in Year 2, and 5.1 million in Year 3. The current spot exchange rate is $1.09/ and the current risk-free rate in the United States is 3.1 percent, compared to that in Europe of 2.9 percent. The appropriate discount rate for the project is estimated to be 10.5 percent, the U.S. cost of capital for the company. In addition, the subsidiary can be sold at the end of three years for an estimated e12.7 million. What is the NPV of the project