Question 190148: A class contains 3 fresh, 4 soph, 6 juniors and 2 seniors. four students are selected at random, find the probability that...
a. all four are juniors
b. no fresh are selected
c. 1 of each year is selected
d.. 2 fresh and 2 juniors
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A class contains 3 fresh, 4 soph, 6 juniors and 2 seniors. four students are selected at random, find the probability that...
a. P(all four are juniors) = 6C4/15C4 = 15/1365 = 0.01099..
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b. P(no fresh are selected) = 12C4/15C4 = 495/1365
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c. P(1 of each year is selected) = (3+4+6+2)/1365 = 15/1365
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d.. P(2 fresh and 2 juniors) = [3C2 + 6C2]/15C4 = (3 + 15)/1365 = 18/1365
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Cheers,
Stan H.
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