- A black card that is black on both sides,
- A white card that is white on both sides, and
- A mixed card that is black on one side and white on the other.
I'm posting one puzzle, riddle, math, or statistical problem a day. Try to answer each one and post your answers in the comments section. I'll post the answer the next day. Even if you have the same answer as someone else, feel free to put up your answer, too!
Thursday, March 18, 2010
Suppose there are three cards:
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2/3. There are three black sides in the hat, each of which is equally likely to be placed facing up. Two of them have black on their reverse.ReplyDelete
50/50 I would say there are only two cards with black. There for pulling one car with black side up means there is either the option the other side is white or black, therefore 50/50.ReplyDelete
I would say 1/2.ReplyDelete
Since the side facing up is black in color, the side facing down can white or black.
Thus the probablity of the other side being Black is 1/2.
The answer may be counter-intuitive, but I love questions like this. Take a look at the whole background and answer on wikipedia: http://en.wikipedia.org/wiki/Bertrand%27s_box_paradoxReplyDelete