Facebook in Scotland has decided to expand one of its branches. They will either sign a 15-year lease or buy a building. Buying a new office building will cost 60 000 000 right now. The other option is to lease a building, which is 4 000 000 payable at the beginning of each year. In either case, the company must pay city taxes, maintenance, and utilities, which are 2 000 000/year, payable at the end of the year. The office will be active for 15 years. If they buy the building, they will then sell it, for an estimated 150 000 000. What rate of return will Facebook receive by buying the office building instead of leasing it?