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Use the normal approximation to the binomial distribution to answer this question. fifteen percent of all students at a large university are absent on mondays. if a random sample of 12 names is called on a monday, what is the probability that four students are absent?

Pls! does anybody know a shortcut for answering these types of questions in the future?

The difference of three and the reciprocal of a number is equal to the quotient of 20 and the number. find the number.