Probabilities can change based off what is known...
With three doors:
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1. When beginning, the chance that the prize is behind any given door is equal. It doesn't matter which door you choose.
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2. Once a door without the prize is opened, the probability of ? doors changes ?
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With four doors:
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1. When beginning, no matter how many doors, the chance that the prize is behind each door is equal.
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2. When opening one door without the prize, the probabilities of the others ? change so that among the three remaining doors the probability that the prize is somewhere is 100%. If you switch everytime you increase your chances of winning compared with staying, but your chances are not as good as in the three door version.
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3. With new information, the probabilities continue to change. With four doors, and 2 opened, switching is an even better strategy than switching in the three door version.
And so on...
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