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Platt Inner circle New York 2025 Posts 
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I'm too dumb to figure out the math. Can somebody help me?
I'm looking down at four face down cards. Each card has a different ESP symbol on its face. I guess which symbol is on each and every card. Then I flip them all over to see how I did. I'd like to know what are the real odds of: Guessing 0 of 4 cards right. Guessing 4 of 4 cards right. Guessing 1 of 4 right. Guessing 2 of 4 right. Thanks.
Sugar Rush is here! Freakishly visual magic. http://www.plattmagic.com
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stanalger Special user St. Louis, MO 998 Posts
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Ah...but you're sharp enough to realize that it's impossible
to guess exactly 3 right! (Assuming you make a different guess for each card.) If you make a different guess for each card, Guessing 0 of 4 cards right: 9/24 = 3/8 = .375 Guessing 4 of 4 cards right: 1/24 =.041666666666666... Guessing 1 of 4 right: 8/24 = 1/3 = .333333333333333... Guessing 2 of 4 right: 6/24 = 1/4 = .25 |
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thoughtsexplorer Elite user Elite... not D-Lite! 424 Posts
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Quote:
On 2007-01-08 11:28, Platt wrote: 0 out of 4: 3/4 x 2/3 x 1/2 (25%) 4 out of 4: 1/4 x 1/3 x 1/2 (approx. 4,2%) The rest is difficult to tell. Dou you mean "exactly" or "at least"? |
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thoughtsexplorer Elite user Elite... not D-Lite! 424 Posts
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So maybe the right answers are already given, and my last question came 2 minutes too late...
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stanalger Special user St. Louis, MO 998 Posts
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Since Platt left out "3",
I assumed he meant "exactly." |
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stanalger Special user St. Louis, MO 998 Posts
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At least 0: 1.0 = 100% (You'll either guess 0, 1, 2, or 4 correct. So you'll
always guess at least 0 correct.) At least 1: 15/24 = .625 = 62.5% At least 2: 7/24 = .29166666666....=29.1666..% At least 3: 1/24 = .04166666... = 4.16666...% All 4: 1/24 = .041666666.... = 4.16666666....% |
Posted: Jan 8, 2007 04:28 pm 