Question 752398: There are 3 black marbles and 4 red marbles in a bag. Trevor will take out 2 marbles without looking.
A. What is the probability that both marbles will be black?
Show your work.
B. Suppose that Trevor takes out 1 marble, replaces it in the bag, then takes out another marble. What is the probability that both marbles will be black in this situation? Show your work.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! There are 3 black marbles and 4 red marbles in a bag. Trevor will take out 2 marbles without looking.
A. What is the probability that both marbles will be black?
Show your work.
Ans: 3C2/7C2 = 3/21 = 1/7
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B. Suppose that Trevor takes out 1 marble, replaces it in the bag, then takes out another marble. What is the probability that both marbles will be black in this situation? Show your work.
Ans: (3/7)^2 = 9/49
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Cheers,
Stan H.
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