SOLUTION: Five black balls numbered 1,2,3,4, and 5 and seven white balls numbered 1,2,3,4,5,6, and 7 are placed in an urn. If one is chosen at random, what is the probability that it is num

Question 45363: Five black balls numbered 1,2,3,4, and 5 and seven white balls numbered 1,2,3,4,5,6, and 7 are placed in an urn. If one is chosen at random, what is the probability that it is numbered 5 or that it is white? and What is the probability that it is numbered 5 given that it is white?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Five black balls numbered 1,2,3,4, and 5 and seven white balls numbered 1,2,3,4,5,6, and 7 are placed in an urn.
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If one is chosen at random, what is the probability that it is numbered 5 or that it is white?
Prob(5 or white) = Prob(5) + Prob(white) - Prob(5 and white)
=2/12 + 7/12 - 1/12 = 8/12= 2/3
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What is the probability that it is numbered 5 given that it is white?
Prob(5 given white) = [Prob(5 and white)]/[Prob(white)]
=[1/12]/[7/12] = 1/7
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Cheers,
Stan H.
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