A 1997 article in The New York Times discussed how long it would take for Bill Gates, the world's second richest person at the time (behind Sultan of Brunei), to become the world's first trillionaire. His birthday is October 28, 1955, and on July 16 , 1997, he was worth $42 billion. (Note: A trillion dolloars is 1000 billion dollars). 6.1 Assume that Bill Gates's fortune grows at an annual rate of 58%, the historical growth rate through 1997 of Microsoft stock, which made up most of his wealth in 1997. Find the age at which he becomes a trillionaire. Interest is compounded annually. 6.2 Repeat part 6.1 using 10,5% growth, the average return on all stocks since 1926. 6.3 What rate of growth would be necessary for Bill Gates to become a trillionaire by the time he is eligible for Social Security on January 01, 2022, after he has turned 66 ? 6.4 Forbes magazine's listings of billionaires for 2006 and 2010 have given Bill Gates's worth as roughly $50 billion and 53 billion, respectively. What was the rate of growth of his wealth between 2006 and 2010