An investor buys the IBM stock. If the probability of the stock price to increase in any trading day is 0.65 and the
probability of the stock price to decrease is 0.35, what is the probability of the IBM stock price to increase in at
least 3 days within 5 trading days?
请教怎么计算出P(3)、P(4)、P(5)
答案0.7648