Ira Schwab wins the lottery and decides to take the one lump sum of $500,000 minus taxes. Ira receives a check for $300,000 after taxes. Using the rule of 72, determine a. How long will it take him to get $600,000 if he can earn 3 percent? b. How long will it take him to get $600,000 if he can earn 6 percent? c. How long will it take him to get $1,200,000 if he can earn 9 percent?

Please show work.