The price of Matterhorn Mining stock is 100 Swiss francs (SFr). During each of the next two six-month periods the price may either rise by 25 percent or fall by 20 percent (equivalent to a standard deviation of 31.5 percent a year). At month 6 the company will pay a dividend of SFr20. The interest rate is 10 percent per six-month period. What is the value of a one-year American call option with an exercise price of SFr80? Now recalculate the option value, assuming that the dividend is equal to 20 percent of the with dividend stock price.