SOLUTION: A box contain 15 pencils of same shape and size, but with different colors, 3 of them are of black, 6 white, 2 red and 4 yellow. Two pencils are drawn at random. Find the probab

Question 176892: A box contain 15 pencils of same shape and size, but with different colors,
3 of them are of black, 6 white, 2 red and 4 yellow. Two pencils are drawn at random.
Find the probability that they are : 1) black or white 2)One red and other black

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A box contain 15 pencils of same shape and size, but with different colors,
3 of them are of black, 6 white, 2 red and 4 yellow. Two pencils are drawn at random.
Find the probability that they are :
1) black or white
black and white are mutually exclusive, so:
P(black or white) = P(black) + P(white) = (3/15) + (6/15) = 9/15 = 3/5
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2)One red and other black
red and black are mutually exclusive events, so:
P(r and b) = P(r)*P(b|r) = (2/15)(3/14) = 9/210 = 3/70
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Cheers,
Stan H.
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