3 A trading company has ten computers that it uses to trade

(3) A trading company has ten computers that it uses to trade on the New York Stock Exchange. The probability of a computer failing in a day is 0.003 and the computers fail independently. Computers are repaired in the evening and each day is an independent trial. a. What is the probability that exactly 3 computers fail in a day? b. What is the probability that a week passes till exactly 3 computers fail? [Hint: consider the probability of exactly n computers failing in a day as a single probability of success for the number of days until n failures occur] c. What is the mean number of days until all ten computers fail in the same day?

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