Chapter 5: Q T5.12. (page 337)
Three machines鈥擜, B, and C鈥攁re used to produce a large quantity of identical parts at a factory. Machine A produces of the parts, while Machines B and C produce and of the parts, respectively. Historical records indicate that of the parts produced by Machine A are defective, compared with for Machine B and for Machine C.
(a) Draw a tree diagram to represent this chance process.
(b) If we choose a part produced by one of these three machines, what鈥檚 the probability that it鈥檚 defective? Show your work.
(c) If a part is inspected and found to be defective, which machine is most likely to have produced it? Give appropriate evidence to support your answer.
Short Answer
Part (b) The probability is
Part (c) Machine B.
Part (a) The tree diagram is


