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Marbles

by tsmith93 » Fri Mar 26, 2010 5:33 am
A jar contains 20 marbles: 4 red, 6 white, and 10 blue. If you remove 1 marble at a time, randomly, what is the minimum you must remove to be certain that you have in your hand at least two marbles of each color?

(a) 6
(b) 10
(c) 12
(d) 16
(e) 18
Last edited by tsmith93 on Fri Mar 26, 2010 5:54 am, edited 1 time in total.
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by eaakbari » Fri Mar 26, 2010 5:42 am
Hmm Unsure is OA = A
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by tsmith93 » Fri Mar 26, 2010 6:10 am
I figured it out, the answer would be (e)18 because you could pull out 10 marbles and have all of them be blue. Then you could pull out the next 6 marbles and all of them be white, then to be sure that you would have at least 2 of every color in your hand, you would need to pull out 2 more, and those would have to be red. Therefore you would have pulled out 18 to be CERTAIN that you have AT LEAST 2 of every color in your hand.
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by eaakbari » Fri Mar 26, 2010 6:18 am
Oh yes your right. I mistook the question as at least 2 in the bag and was hence getting confused. Thanks
As they say these silly mistakes can cost you dearly, very dearly.
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