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A bag contains 10 red marbles, 6 white marbles, and 9 blue marbles.
You draw 4 marbles out at random, without replacement.
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(a) What is the probability that all the marbles are red?
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(b) What is the probability that exactly two of the marbles are red?
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(c) What is the probability that none of the marbles are red?
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In all, there are 10 + 6 + 9 = 25 marbles.
Of them, 10 are red; 6+9 = 15 are NOT red.
(a) The total number of different quadruples is = = 12650.
This number goes to the denominator.
In part (a), the number of favorable cases is = = 210.
The probability is P = = = 0.0166 (rounded). ANSWER
(b) In part (b), the number of favorable cases is = = 45*105 = 4725.
The probability is P = = = 0.3735 (rounded). ANSWER
(c) P = = 0.1079 (rounded). ANSWER
Solved in full.
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