Question 205975: Can anyone help with this?
A box contains 10 green, 2 red, 7 yellow, and 6 blue marbles. Four marbles are drawn from the box without replacement.
a) What is the probability that all four marbles are the same color?
b) What is the probability that none of the marbles is yellow?
c) What is the probability that you get one marble of each color?
I think a) is 21C4 I am confusing myself on the rest. I was using a sample space to try to figure it out. (g,r) (g,y) (g,b) (g,g) and so forth and came up with 16 combination's of sets. Am I on the right track? thanks!!!
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Can anyone help with this?
A box contains 10 green, 2 red, 7 yellow, and 6 blue marbles. Four marbles are drawn from the box without replacement.
a) What is the probability that all four marbles are the same color?
P(4 of same color) = P(4green or 4yellow or 4 blue)
= [10C4 + 7C4 + 6C4]/25C4 = [210+35+15]/12650 = 0.0206
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b) What is the probability that none of the marbles is yellow?
That means you are selecting from 18 instead of 25 marbles
P(no yellow) = 18C4/25C4
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c) What is the probability that you get one marble of each color?
[10*2*7*6]/25C4
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I think a) is 21C4 I am confusing myself on the rest. I was using a sample space to try to figure it out. (g,r) (g,y) (g,b) (g,g) and so forth and came up with 16 combination's of sets. Am I on the right track? thanks!!!
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Comment: Your samplel space would have to have 4-tuples in it since you
are selecting 4 marbles. Each would look like (-,-,-,-)
and there would be 12650 of them.
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Cheers,
Stan H.
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