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A shelf in the Metro Department Store contains 85 colored ink cartridges for a popular ink-jet printer. Six of the cartridges are defective.

AIf a customer selects 3 cartridges at random from the shelf, what is the probability that they are all defective? (Round your answer to five decimal places.)



BIf a customer selects 3 cartridges at random from the shelf, what is the probability that at least 1 is defective? (Round your answer to three decimal places.)

Verified Answer :

toporc
AThe probability that all 3 are defective in a sample of 3 is:
\(P(3)=\frac{6C3}{85C3}=0.00020\)

(b) The probability that none are defective is:
\(P(0)=\frac{79C3}{85C3}=0.800\)
Therefore the probability that at least one is defective is:
1 - 0.800 = 0.200