An urn contains ten marbles, of which five are green, two are blue, and three are red. Three marbles are to be drawn from the urn, one at a time without replacement. What is the probability that all three marbles drawn will be green?
The probability of choosing a green marbles on the first draw is
Since we do not put it back, there are 9 marbles, 4 of which are green. The second green has probability
Now there are 8 marbles, 3 of which are green,
So, the probability that all three marbles drawn are green
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