SOLUTION: Three screws are drawn at random from a lot of 100 screws, 10 of which are defective. Find the probability of an event that all three screws drawn are non defective, assuming that

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Question 724259: Three screws are drawn at random from a lot of 100 screws, 10 of which are defective. Find the probability of an event that all three screws drawn are non defective, assuming that we draw
(a) with replacement
(b) without replacement
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Three screws are drawn at random from a lot of 100 screws, 10 of which are defective. Find the probability of an event that all three screws drawn are non defective, assuming that we draw
a) with replacement
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Binomial problem with n = 3 ; p(defect) = 0.1 ; p(not defect) = 0.9
P(3 not defective) = 0.9^3 = 0.729
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(b) without replacement
# of ways to succeed: 90C3
# of possible outcomes: 100C3
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P(3 not defective) = 90C3/100C3 = 0.7265
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Cheers,
Stan H.