E 243 Recitation Problems for Friday, September 11, 2009 Instructor’s Sample Problems: 1) Inspector A visually examines 1000 bowls and finds flaws in 37 of them. Inspector B examines the same 1000 bowls and finds flaws in 43 of them. A total of 948 bowls were found to be flawless by both inspectors. One of these bowls is selected at random. a) What is the probability that a flaw was found in this bowl by at least one of the inspectors? b) What is the probability that flaws in this bowl were found by both inspectors? c) What is the probability that a flaw was found by inspector A but not by inspector B? 2a) In how many ways can a multiple choice test be answered if it consists of 5 questions each having 4 possible answers of which only one is correct and the student checks just one of these for each question? b) In how many ways can a student check off one answer for each question and answer all 5 questions incorrectly? c) What is the probability that a random selection of answers will result in the student
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