[Exer6-2] Exercise 47 of Book {Devore2017B} P.125
A company that produces fine crystal knows from experience that $10\%$ of its goblets have cosmetic flaws and must be classified as "seconds."
- (a) Among six randomly selected goblets, how likely is it that only one is a second?
- (b) Among six randomly selected goblets, what is the probability that at least two are seconds?
- (c) If goblets are examined one by one, what is the probability that at most five must be selected to find four that are not seconds?