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On November 21 2004 21:10 FakeSteve[TPR] wrote:Show nested quote +On November 21 2004 20:58 Famouzze wrote:
sure, it's very counter-intuitive so here's the explanation. the mother has 2 children, with four possible and equally likely gender outcomes: two girls (GG), one girl then one boy (GB), one boy then one girl (BG), or two boys (BB). if you know one of the children is a girl, then that eliminates the possibility of BB. the 3 other possiblities remain, each equally likely :D. if you dont know which of the two children is older, GB and BG are the same thing
The analogy I used to understand the 2/3 is by flipping 2 quarters, since they are 50/50 just like babies. Flip 2 quarters up into the air, and let them hit the ground. The odds are, 1 of them is heads, and one of them is tails. Go over to one of them on the ground and look at it. If it is heads, the other one has a higher chance of being tails. If it is tails, the other one has a higher chance of being heads. Get a couple of quarters and try it! ;p
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i dont get why its implied only 1 husband can cheat per day. why cant 45 cheat the freaking same day? -_-
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On November 21 2004 20:41 seeyoulater wrote:Show nested quote +On November 21 2004 20:36 baal wrote:On November 21 2004 20:24 LTT wrote:
I don't want to go through the calculations, but it's obviously based on the time delay. Like for the monk puzzle, assuming the monks are smart, say that there are 5 monks 3 of which have red eyes. So each monk with red eyes sees two other monks with red eyes. After two midnights of no suicides, all three monks will commit suicide. they dont know how many have red eyes -_- duh! The tourist says at least one of you has red eyes. The 1 guy that has red eyes will look around, see everyone else's brown eyes, and kill himself. If there are 2, one of the people with red eyes will see the other guy with red eyes and assume that he can come up with the same reasoning above to kill himself the first night. If he didn't kill himself, that means he has red eyes as well. So on to infinity.
smart, but not to infinity, monk suicide will stop when the last red-eye monk kill himself. could be a happy ending afterall ^^
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On November 21 2004 21:25 hifi wrote:Show nested quote +On November 21 2004 20:41 seeyoulater wrote:On November 21 2004 20:36 baal wrote:On November 21 2004 20:24 LTT wrote:
I don't want to go through the calculations, but it's obviously based on the time delay. Like for the monk puzzle, assuming the monks are smart, say that there are 5 monks 3 of which have red eyes. So each monk with red eyes sees two other monks with red eyes. After two midnights of no suicides, all three monks will commit suicide. they dont know how many have red eyes -_- duh! The tourist says at least one of you has red eyes. The 1 guy that has red eyes will look around, see everyone else's brown eyes, and kill himself. If there are 2, one of the people with red eyes will see the other guy with red eyes and assume that he can come up with the same reasoning above to kill himself the first night. If he didn't kill himself, that means he has red eyes as well. So on to infinity. smart, but not to infinity, monk suicide will stop when the last red-eye monk kill himself. could be a happy ending afterall ^^
I think he means that the logic applies to however many red-eyed monks there are
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Kyrgyz Republic1462 Posts
The analogy I used to understand the 2/3 is by flipping 2 quarters, since they are 50/50 just like babies. Flip 2 quarters up into the air, and let them hit the ground. The odds are, 1 of them is heads, and one of them is tails. Go over to one of them on the ground and look at it. If it is heads, the other one has a higher chance of being tails. If it is tails, the other one has a higher chance of being heads. Get a couple of quarters and try it! ;p
So if that is right, let's flip two coins. Then look at the first one, if it's tails, you say the other's heads, and vice versa. From what you say, you will win 66% of the time. Thus, if you're wrong, you give me 66$, and if you are right, I give you $33. Let's try doing this 1000 times.
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most of these riddles aren't good riddles.
:-(
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Kyrgyz Republic1462 Posts
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Valhalla18444 Posts
On November 21 2004 21:15 seeyoulater wrote:Show nested quote +On November 21 2004 21:10 FakeSteve[TPR] wrote:On November 21 2004 20:58 Famouzze wrote:
sure, it's very counter-intuitive so here's the explanation. the mother has 2 children, with four possible and equally likely gender outcomes: two girls (GG), one girl then one boy (GB), one boy then one girl (BG), or two boys (BB). if you know one of the children is a girl, then that eliminates the possibility of BB. the 3 other possiblities remain, each equally likely :D. if you dont know which of the two children is older, GB and BG are the same thing The analogy I used to understand the 2/3 is by flipping 2 quarters, since they are 50/50 just like babies. Flip 2 quarters up into the air, and let them hit the ground. The odds are, 1 of them is heads, and one of them is tails. Go over to one of them on the ground and look at it. If it is heads, the other one has a higher chance of being tails. If it is tails, the other one has a higher chance of being heads. Get a couple of quarters and try it! ;p
that isnt how probability works =[
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Maybe we should just bear in mind that this answer is correct
But only in terms of mathematical statistics, that in itself assumes that Girl and then Boy, and Boy and then Girl are two different possibilities, as opposed to looking at it in terms of something else that assumes that those possibilities are the same... anyway, how many answers for this question are there anyway 
By no means is this "The" right answer
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On November 21 2004 21:36 Random() wrote:Show nested quote +
The analogy I used to understand the 2/3 is by flipping 2 quarters, since they are 50/50 just like babies. Flip 2 quarters up into the air, and let them hit the ground. The odds are, 1 of them is heads, and one of them is tails. Go over to one of them on the ground and look at it. If it is heads, the other one has a higher chance of being tails. If it is tails, the other one has a higher chance of being heads. Get a couple of quarters and try it! ;p
So if that is right, let's flip two coins. Then look at the first one, if it's tails, you say the other's heads, and vice versa. From what you say, you will win 66% of the time. Thus, if you're wrong, you give me 66$, and if you are right, I give you $33. Let's try doing this 1000 times.
Ya what he wrote doesn't work. The second you know the result of one of the coins one possible combination for the 4 coins together is taken away which means odds are back to 50. Even though they were tossed at the same time they become independant each other when you look at them seperategly or "one after the other."
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Kyrgyz Republic1462 Posts
So if you take into account their relative age....
The child who answered is 1, other is 2. Younger is y, elder is e.
These are the possible outcomes: (the first one is that who answered the door)
(GyGe, GeGy, GeBy, GyBe, BeGy, ByGe, ByBe, BeBy)
Now we know 1 is G, the other one could be:
(Ge, Gy, By, Be)
Which is what, huh, 50%?
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On November 21 2004 21:57 Famouzze wrote:
nono, its a 2/3 chance the other child is a boy. 1/3 its a girl. the only option out of GG BG GB BB thats eliminated when u see one child is a girl is BB.
But I think that logic is flawed. You rule out the age factor for the (GG) option when you put it like that. She could have: an older brother, a younger brother, an older siter or a younger sister. Thats 50/50 for gender.
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What logic isn't flawed? The nature of logic is to be flawed so that it can be applied, for no logic can take into consideration all factors, no logic we can comprehend.
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On November 21 2004 22:01 Random() wrote:
So if you take into account their relative age....
The child who answered is 1, other is 2. Younger is y, elder is e.
These are the possible outcomes: (the first one is that who answered the door)
(GyGe, GeGy, GeBy, GyBe, BeGy, ByGe, ByBe, BeBy)
Now we know 1 is G, the other one could be:
(Ge, Gy, By, Be)
Which is what, huh, 50%?
you're not taking into account the other sibling. ge gy by be is the same thing as saying g or b, which applies to any given person. if you know the child has one sibling and that sibling is a girl it changes things.
the remaining options in your example would be gyge gegy geby byge begy gybe, all the same six from the eight options you listed minus bybe and beby
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On November 21 2004 20:50 Famouzze wrote:
yah, thats what i think is the hardest, even though its the same concept. i love those two....i know so many ppl who refuse to believe its 2/3 and not 1/2 lol
Actually to burst your Bubbles if You have NO IDEA what gender her children are and One of them is a girl then it is still 100% Uncertain(50/50) Whether its a boy or Girl. Now with the door problem it does Move up to 2/3rds. It has to do with the inherrent nature of chosing and guessing and the differances of the two.
And No I am not refusing to beleive its 2/3rds. There is Absolutely no Rule anywhere that says if a woman has 2 kids and 1 is a girl then the other is obviously more likely a Boy.
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EPT
