There's an answer to this question here on Chegg Study but it only shows the answers. It lacks of explanation and calculations. I simply cannot make sense out of it so I'm looking for another answer please.

Question: An investment requires an initial disbursement of 2,500,000 and the duration of the project is 3 years, in the first of which it generates a cash flow of 1,500,000, in the second 3,700,000 and the third 4,100,000.

a) Calculate the Net Present Value of the investment, knowing that inflation is 3% cumulative annually and that the required profitability in the absence of inflation is 8%.

b) Calculate the actual internal rate of return of the previous investment.