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Topic: Hard-boiled eggs (Read 699 times) |
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Eigenray
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Hard-boiled eggs
« on: Nov 16th, 2005, 9:26am » |
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Some idiot boiled 3 eggs and put them back in the carton with 3 raw eggs (actually I he boiled 6 but only put 3 back to use later, but that's irrelevant). Of course he didn't label them or anything because he just assumed he'd be able to remember which were which. The question is twofold.
1) How can he tell them apart?
2) If you randomly crack open eggs until you find all 3 cooked ones, what's the expected number you will go through?
a) More generally, what if there are M raw and N cooked?
b) What if you stop as soon as you are able to determine which eggs are which?
(One would expect this to have been asked before, but any regular can guess what happens if you try searching for "egg".)
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Grimbal
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Re: Hard-boiled eggs
« Reply #1 on: Nov 16th, 2005, 9:46am » |
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1) if he is fast enough, the cooked ones should still be hot.
Or he can cook them all.
but the usual trick is to make them spin. Cooked eggs spin easily, raw eggs don't
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Three Hands
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Re: Hard-boiled eggs
« Reply #2 on: Nov 16th, 2005, 11:09am » |
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An addition to Grimbal's suggestion:
Spin the egg, then stop it and release it. If the egg starts to spin again, it is raw. If it stays stopped, it is cooked - at least, it works for hard-boiled eggs
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towr
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Re: Hard-boiled eggs
« Reply #3 on: Nov 16th, 2005, 2:35pm » |
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You can usually shake them to find out which are boiled and which aren't.
The boiled ones don't sound like anything much, the raw ones sound like they have liquid inside, which they do.
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beatsamurai
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Re: Hard-boiled eggs
« Reply #4 on: Nov 16th, 2005, 3:32pm » |
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I've never tried it but I bet this would work:
| hidden: | | Hold a bright light behind the egg. I imagine a raw egg would be slightly translucent and you'd be able to make out the yolk. The hard-boiled ones would likely not let the light through as easily. |
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Grimbal
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Re: Hard-boiled eggs
« Reply #5 on: Nov 17th, 2005, 12:57am » |
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If you wait enough, will they stink differently?
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otter
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Re: Hard-boiled eggs
« Reply #6 on: Nov 17th, 2005, 6:07am » |
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on Nov 16th, 2005, 3:32pm, beatsamurai wrote:I've never tried it but I bet this would work:
| hidden: | | Hold a bright light behind the egg. I imagine a raw egg would be slightly translucent and you'd be able to make out the yolk. The hard-boiled ones would likely not let the light through as easily. |
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This is called "candling" an egg. You are correct. As light passes through a raw egg, the "white" of the egg will transmit light and the yolk will be clearly visible. A hard-boiled egg will not transmit light readily and the internal features will not be distinguishable.
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We shall not cease from exploration. And the end of all our exploring will be to arrive where we started
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Grimbal
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Re: Hard-boiled eggs
« Reply #7 on: Nov 20th, 2005, 9:20am » |
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A boiled egg in the morning is hard to beat.
Btw, why does it say "hard" and is in the easy forum?
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towr
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Re: Hard-boiled eggs
« Reply #8 on: Nov 20th, 2005, 11:03am » |
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on Nov 20th, 2005, 9:20am, Grimbal wrote:| Btw, why does it say "hard" and is in the easy forum? |
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Because the egg is hard-boiled, rather than soft and snotty..
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Dynasty
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Re: Hard-boiled eggs
« Reply #9 on: Nov 20th, 2005, 12:25pm » |
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if you're looking for a probability independent of the characteristics of raw and hard boiled eggs, i believe it would be....
| hidden: | Wouldn't the number of expected eggs to go through be 5.5?
in terms of M and N.... where M = number of cooked eggs and N = number of raw eggs
M+N - (1- M/(M+N))
am I way off here? lol |
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Eigenray
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Re: Hard-boiled eggs
« Reply #10 on: Nov 24th, 2005, 10:49am » |
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Yeah. Are most people aware of this? It was something I'd always known somehow, but then I asked someone the other day and he hadn't heard it. Anyway, Three Hands's answer is the one I use in practice.
on Nov 20th, 2005, 12:25pm, Dynasty wrote:| if you're looking for a probability independent of the characteristics of raw and hard boiled eggs, i believe it would be.... |
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No... what's your reasoning?
For example, if N=M=2, there are 6 possibilities:
OOXX : 2
OXOX : 3
XOOX : 3
OXXO : 4
XOXO : 4
XXOO : 4,
for an expected value of 20/6 eggs checked.
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