The "Brasher doubloon," which was featured in the plot of the Raymond Chandler novel, The High Window, was sold at auction in 2018 for $5.5 million. The coin had a face value of $15 when it was first issued in 1787 and had been previously sold for $430,000 in 1979.
a. At what annual rate of return did the coin appreciate from its minting to the 1979 sale? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.)
b. What annual rate of return did the 1979 buyer earn on his purchase? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.)
c. At what annual rate of return did the coin appreciate from its minting to the 2014 sale? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.)