A batch of 400 sewing machines contains 6 that aredefective.
(a) Three sewing machines are selected at random, withoutreplacement. What is the probability that the second sewing machineis defective, but the first and third are acceptable?
(b) Three sewing machines are selected at random, withoutreplacement. What is the probability that the third sewing machineis defective, given that the first two are acceptable?
(c) Sewing machines are selected, this time with replacement.What is the probability that the tenth machine selected is thefirst defective one?
(d) Sewing machines are selected, with replacement. What is theexpected number of machines selected until you find two defectiveones?
