Question 903413: Could you please explain how to work this problem? A box contains 18 microchips, of which 5 are defective. If 3 chips are selected at random from the box, what is the probability that none of them are defective?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Could you please explain how to work this problem? A box contains 18 microchips, of which 5 are defective. If 3 chips are selected at random from the box, what is the probability that none of them are defective?
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Note: 5 are defective, so 13 are not defective
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P(none of the 3 is defective) = P(all 3 are good)
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# of ways to select 3 that are not defective:: 13C3 = 286 ways
# of random sets of 3 chips:: 18C3 = 816
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Ans: P(none of 3 are defective) = 286/816
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Cheers,
Stan H.
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