Question 222378: There are 7 black, 10 blue, 2 red, and 1 yellow marbles. What is the probability of selecting a black marble and then a blue marble if the marbles are replaced?
What is the probability if the marbles are not replaced?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! There are 7 black, 10 blue, 2 red, and 1 yellow marbles. What is the probability of selecting a black marble and then a blue marble if the marbles are replaced?
If replaced the events are independent.
P(black then blue) = P(black)*P(blue) = (7/20)*(10/20) = 4/40
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What is the probability if the marbles are not replaced?
If not replaced the events are dependent.
P(black then blue) = P(black)*P(blue|black) = (7/20)*(10/19) = 7/38
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Cheers,
Stan H.
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