Question 221751: an urn contains 4 red, 2 white, and 4 blue marbles. In how many ways can three marbles be selected so that at least one of them is blue?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! an urn contains 4 red, 2 white, and 4 blue marbles. In how many ways can three marbles be selected so that at least one of them is blue?
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P(no blue) + P(at least one blue) = 1
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So, P(at least one blue) = 1 - P(no blue)
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P(none blue) = 6C3/10C3 = 20/120 = 1/6
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Therefore: P(at least one blue) = 1-(1/6) = 5/6
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Cheers,
Stan H.
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