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EXERCISE 5 A stock price is currently $30. During each 2-months period for the next 4 months it will increase by 8% or reduce by 10%. The risk-free interest rate is 5%. Use A 2-period binomial model to calculate the value of a derivative that pays off V = [(30 - S)+12, where S, is the stock price at the second step of the binomial tree, so after 4 months. If the derivative is American-style, should it be exercised early