Assume the price St of IBM at time t satisfies the log-normal model with volatility 20% and expected rate of return 12%. The spot price is $30. The risk-free rate is 3%. Consider a 1-year IBM butterfly spread made of calls with strike price 30, 34 and 38. Compute the probability that the payoff of the butterfly in 1 year is zero. Assume the price St of IBM at time t satisfies the log-normal model with volatility 20% and expected rate of return 12%. The spot price is $30. The risk-free rate is 3%. Consider a 1-year IBM butterfly spread made of calls with strike price 30, 34 and 38. Compute the probability that the payoff of the butterfly in 1 year is zero