A private wind power generation company in the south of the country made the following estimates (in thousands of pesos) for a new wind farm. The discount rate is 10% per year and the life of the project is 25 years. Calculate a) the rate of return and b) the modified B/C ratio

Benefits: $20,000 in year 0 and $30,000 in year 5

Savings: $2,000 in years 1-20

Cost: $50,000 in year 0

Disadvantages: $3,000 in years 1-10