Michael C. answered • 03/16/17
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1) With 12 red and 28 blue, the probability of choosing a blue in a random draw would be 28/40 = 7/10 = 0.7
2) If he did not replace the blue marble at first draw, then there will be 27 blue and 12 red remaining = 39 marbles
Probability of choosing a red in this second draw is = 12/39 = 4/13 = 0.308
Michael C.
Absolutely, my answer was incomplete, its one probability and is:
{probability of a red on second throw given a blue on first which was not replaced} = 4/13 * 7/10 = 28/130 = 0.215
Thanks Arthur much appreciated
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03/16/17
Arthur D.
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You're very welcome, Michael.
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03/16/17
Arthur D.
03/16/17