Pauline pays $5 million for a 7-year lease of a building and rented it out. She will receive $1 million rental income at the end of the first and the second year, and will receive $1.2 million at the end of the remaining years. Calculate the internal rate of return of her investment. What is the internal rate of return if there is an additional income of $0.5 million at 7.5 years.