61. A company that produces ne crystal knows from experience that 10% of its goblets have cosmetic aws and must be classi ed 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 ve must be selected to nd four that are not seconds?