Suppose that a stock price is currently 64 dollars, and it is known that at the end of each of the next two six-month periods, the price will be either 18 percent higher or 18 percent lower than at the beginning of the period. Find the value of an American put option on the stock that expires a year from now, and has a strike price of 68 dollars. Assume that no arbitrage opportunities exist, and a risk-free interest rate of 8 percent.
Answer = dollars.