Three red and two blue balls are placed in a hat. A ball is chosen at random and not replaced. A second ball is chosen at random. What is the probability that both balls chosen will be blue.
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Three red and two blue balls are placed in a hat. A ball is chosen at random and not replaced. A second ball is chosen at random. What is the probability that both balls chosen will be blue.
The 1st ball probability is 2 / 5
If the first ball is blue, there's only one blue ball in the hat, so ...
The 2nd ball probability is 1 / 4
Probability of both happening is (2 / 5) x (1 / 4) = 2 / 20 = 1 / 10
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