2.1.41 A batch of 140 semiconductor chips is inspected by choosing a sample of a chips. Assume 10 of the chips do not conform to customer requirements. (a) How many different samples are possible? (b) How many samples of five contain exactly one nonconforming chip? (c) How many samples of five contain at least one nonconforming chip? 2.1.45 Consider the design of a communication apater (a) How many three-digit phone prefixes that are used to represent a particular geographic area (such as an area crude ) can be created from the digits 0) to 9? (b) As in part (a), how many three -digit phone prefixes are possible that do not start with o or I but contain 0 or I in the micklle digit ? (e) How many three -digit phone prefixes are possible in which no digit appous more than oner ? 2.1.47 In a chemical plant, 24 holding tanks are used for final product storage. Four tanks are selected at random a and without replacement . Suppose that six of the tanks contain material in which the viscority coords ciromer requirements (a) What is the probability that canctly one tank in the summple contains high -viscocity ma - Lerial ? (b) What is the probability that at least one tank in the simple contains high -vivocity (c) In addition to the six tanks with high viscocity levels , four different tanks contain ma- Lerial with high impurities . What is the probability that exactly one tank in the sample contains high -visencity material , and exactly one tank in the sample contains material with high impurities ? 2.1.44 Plastic parts produced by an injection molding operation are checked for conformance to spec - ifications . Each tool contains 12 cavities i in which parts are produend , and these parts fall into A conveyor when the press opens . An inspector chocks 1 parts from among 12 at random Two critics are affected by temperature malfunction that results in parts that do not conform to specifications. (a) How many samples contain exactly 1 nonconforming part? (b) How many samples contain at least I nonconforming part