anabanana wrote:

what I don't understand is why this must be a worst case scenario. the question asks for the minimum number that must be removed -- doesn't that mean best case scenario? In which case, wouldn't the answer be 4 red+6 white+2 blue = 12?

The key is in the language of the question: 'the minimum number of marbles removed so that you are

certain', certain being the keyword here. Now you can remove the 12 marbles as you pointed out but can you be certain that you have each kind.

Say you pick twelve: 10 blue and 2 white. Hence no red at in the selection. Hence we assume the worst case scenario.

_________________

Sandy

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