A student takes a multiple choice test where each question has 4 possible answer with only one correct and 3 others wrong. He gets the right answer if he knows it, otherwise he guesses at random. Assume the probability for him to know the answer to a question is 0.8. Suppose there are 100 questions on the test. Let X be the number of correctly answered questions. Assuming X has a Binomial distribution find P(75 < X <= 87)