The incredible shrinking $50 bill in 1957 was worth $50, but in 2007 it is worth only $6.42. a. What was the compounded average annual inflation rate (loss of purchasing power) during this period of time? b. Fifty dollars invested in the stock market in 1957 was worth $1,937 in 2007. In view of your answer to Part (a), what was the annual real interest rate earned on this investment? . . . a. The loss of purchasing power is %. (Round to two decimal places.)