#21
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I agree with Brucez. *NM*
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#22
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Query ...
there are four apples in a basket one of them is laced with sleeping potion a guy picks one at midnight and eats it he falls asleep another guy takes a bite and he falls asleep what is the probability that this is the funny apple? |
#23
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Re: Query ...
1/4 assuming they would fall asleep at midnight regardless. |
#24
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Maybe so, but I was still wrong ...
bit slow as usual but i think i understand it now the result that you see is HH although there were two events leading up to this result the first event of picking has long gone under the bridge the way you can have such a result is by the H/h coin falling HH, Hh, hh, or hH, or the three H/T coins falling HH so there are seven different possible forms of the HH you can see, four of which could be made by the H/h coin and three by the H/T coins hence 4 out of 7 times that you do see HH it is as the result of having picked the H/h coin |
#25
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the question was..
what are the chances you picked the bad coin, not what are the chances you picked the bad coin and flipped it twice and came up with two heads. I think no matter how many times you flip heads, until you flip tails the answer is still 1 in 4...i think |
#26
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Re: the question was..
The fact that the coin came up HH twice is relevant. For instance, if you knew that after flipping the coin twice that it came up TT, the probability that it is the bad coin is 0 (even though initially the probability of picking it was 1/4). |
#27
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1 in 4
Since two flips won't indicate anything, probability-wise |
#28
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4/7
3 fair coins each have 1/4*1/4 1 bad coin has 1/4 chance of being flipped 2 heads 3/16 chance that fair coin was flipped 2 heads 1/4 chance that bad coin was flipped 2 heads thus prob of bad coin is 4/7 peter |
#29
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Re: Do This by Logic
Funny, i got the number 4/7, by a different route (I think) to most others...only read a few after I did it myself. Fair coin gives HH 0.25 of time. Funny coin 1.0 of the time. Just compare the added probabilities for fair and funny coins (ie 0.75 cf 1.0 or 4/7). |
#30
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Re: Do This by Logic
cf ? |
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