Over the past few years, Microsoft founder Bill Gates' net worth has fluctuated between $20 billion and $130 billion. In early 2006, it was $26 billion - afer he reduced his statke in Microsoft from 21% to 14% by moing billions into his charitale foundations. Le'ts see what Bill Gates can do with his money:

a. Manhattan's native tribe sold Manhattan Island to Peter Minuit for $24 in 1626. Now, 387 years later in 2013, Bil Gates wants to buy the island from the "current natives." How much would Bill have to pay for Manhattan if the "current natives" want a 6% annual return on the original $24 purchase price?

b. Bill gates decides to pass on Manhattan and instead plans to buy the city of Seattle, Washington, for $50 billion in 10 years. How much would Bill have to invest today at 9% compounded anually in order to purchase Seatatle in 10 years?

c. Now assume Bill Gates only wants to invest half his net worth today, $13 billion, in order to buy Seattle for $50 billion in 10 years. What annual rate of return would he have ot earn in order to complete his purchase in 10 years?

d. Instead of buying and running large cities, Bill gates is considering quitting from the rigors of the business world and retiring to work on his golf game. To fund his retirement, Bill would invest his $20 billion fortune in safe investments with an expected annual rate of return of 8%. He also wants to make 45 equal annual withdrawals from this retirement fund beginning a year from today, running his retirement fund to $0 at the end of 45 years. How much can his annual withdrawal be in this case?

(I'm using excel's PV, FV, Rate, and PMT functions to solve this)