Question 348557: A sample of 5 balls is to be selected at random from an urn containing 20 balls numbered 1 to 20. Four balls are green, 6 balls are white, and 10 balls are black.
How many samples can be selected that contain at least 1 white ball?
I wrote out all the sample spaces and tried to count them, but that didn't work for me, i must have missed some.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A sample of 5 balls is to be selected at random from an urn containing 20 balls numbered 1 to 20. Four balls are green, 6 balls are white, and 10 balls are black.
How many samples can be selected that contain at least 1 white ball?
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Total # of sets of 20 balls = 20C5
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# with no white balls = 14C5
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# with at least one white ball = 20C5 - 14C5 = 13,502
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Note: I can see where you would lose track of the number
if you wrote out the sample space which as 20C5 = 15,504 sets of 5 in it.
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Cheers,
Stan H.
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