|
|
|
How many 'doses' does each jar contain?
|
|
|
Hmm actually the way I formulated this problem might be problematic, give me a sec to review
|
Kinda depends on how much milk you can get the rats to drink.
are we to suppose that we are able to feed rats milk infinitely fast, that it takes no time to open and close the jars of milk?
|
|
|
can 1 rat drink more than 1 jar of milk? if so only 1 rat will die.
|
+ Show Spoiler +log2(1000) rounded up equals 10 rats.
Each milk is fed to a unique subset of the rats, depending on which subset dies, then you know the milk that was fed to that group was poisoned. With 10 rats, there are 2^10 = 1024 different subsets, which is enough.
|
Hong Kong20321 Posts
|
On May 17 2008 03:17 Elements wrote:+ Show Spoiler +log2(1000) rounded up equals 10 rats.
Each milk is fed to a unique subset of the rats, depending on which subset dies, then you know the milk it came from was poisoned. With 10 rats, there are 2^10 = 1024 different subsets, which is enough.
you have a time limit.
(even though i think this answer is what he wanted the correct answer to the riddle to be, he just made the time limit wrong  )
|
+ Show Spoiler +
My strategy: assumes that even the smallest dose of the poison will kill the rat, you can mix the milk together and still retain the poison, you can split the milk into enough portions, the time of death is exactly 2 hours (not a single second off) and the rat can drink that bloody much.
1 rat. Feed it very, very small sample of a different jar of milk every 3 seconds and note what time it dies.
If you can't measure the time of death that accurately, then simply add more rats and stagger the milk intake, combined with feeding the different rats with different combination of milks
|
On May 17 2008 03:19 travis wrote:Show nested quote +On May 17 2008 03:17 Elements wrote:+ Show Spoiler +log2(1000) rounded up equals 10 rats.
Each milk is fed to a unique subset of the rats, depending on which subset dies, then you know the milk it came from was poisoned. With 10 rats, there are 2^10 = 1024 different subsets, which is enough. you have a time limit. (even though i think this answer is what he wanted the correct answer to the riddle to be, he just made the time limit wrong )
The time limit is no problem, you do it simultanously.
An example might be better:
+ Show Spoiler +with 4 jars and 2 rats,
rat 1 drinks jar 2 and 4
rat 2 drinks jar 3 and 4
two hours later...
if no rats die, it was jar 1
if only rat 1 dies, it was jar 2
if only rat 2 dies, it was jar 3
if both rat 1 and rat 2 die, it was jar 4
|
On May 17 2008 03:23 Elements wrote:Show nested quote +On May 17 2008 03:19 travis wrote:On May 17 2008 03:17 Elements wrote:+ Show Spoiler +log2(1000) rounded up equals 10 rats.
Each milk is fed to a unique subset of the rats, depending on which subset dies, then you know the milk it came from was poisoned. With 10 rats, there are 2^10 = 1024 different subsets, which is enough. you have a time limit. (even though i think this answer is what he wanted the correct answer to the riddle to be, he just made the time limit wrong ) The time limit is no problem, you do it simultanously. An example might be better: + Show Spoiler +with 4 jars and 2 rats,
rat 1 drinks jar 2 and 4
rat 2 drinks jar 3 and 4
two hours later...
if no rats die, it was jar 1
if only rat 1 dies, it was jar 2
if only rat 2 dies, it was jar 3
if both rat 1 and rat 2 die, it was jar 4
yes but u have to wait 2 hours so by the time u get it narrowed down to less jars, you have no time let to do a second wave of experiments
|
So the main thing I wanted to avoid was gold rush's answer which utilizes time to figure out when the rats die.
It should be that you cannot really discern any information about when the rats died, and therefore should be unable to figure out when the rat died simply by time.
@travis
The rats have infinite capacity, and you have the ability to feed the rats any amount of milk instantly. The main reason for the time limit is to make sure you can't feed the rats poison after a rat has already died.
@Elements
Congratulations you have solved the problem.
|
On May 17 2008 03:25 travis wrote:Show nested quote +On May 17 2008 03:23 Elements wrote:On May 17 2008 03:19 travis wrote:On May 17 2008 03:17 Elements wrote:+ Show Spoiler +log2(1000) rounded up equals 10 rats.
Each milk is fed to a unique subset of the rats, depending on which subset dies, then you know the milk it came from was poisoned. With 10 rats, there are 2^10 = 1024 different subsets, which is enough. you have a time limit. (even though i think this answer is what he wanted the correct answer to the riddle to be, he just made the time limit wrong ) The time limit is no problem, you do it simultanously. An example might be better: + Show Spoiler +with 4 jars and 2 rats,
rat 1 drinks jar 2 and 4
rat 2 drinks jar 3 and 4
two hours later...
if no rats die, it was jar 1
if only rat 1 dies, it was jar 2
if only rat 2 dies, it was jar 3
if both rat 1 and rat 2 die, it was jar 4
yes but u have to wait 2 hours so by the time u get it narrowed down to less jars, you have no time let to do a second wave of experiments
Thing is, after the first time, you already know exactly what jar it is. You haven't narrowed down the possibility; you've found the only jar that could be poison.
|
On May 17 2008 03:20 goldrush wrote:+ Show Spoiler +
My strategy: assumes that even the smallest dose of the poison will kill the rat, you can mix the milk together and still retain the poison, you can split the milk into enough portions, the time of death is exactly 2 hours (not a single second off) and the rat can drink that bloody much.
1 rat. Feed it very, very small sample of a different jar of milk every 3 seconds and note what time it dies.
If you can't measure the time of death that accurately, then simply add more rats and stagger the milk intake, combined with feeding the different rats with different combination of milks
well given the specificity of the rules I would have to say this is a very clever answer. though it would never workd in the real world cuz digestion doesn't work like that hehe
|
I am so confused by what you guys are saying right now. with a 2 hour delay, how can u possibly find out with only 10 rats?
let's say it's the 50th jar out of the 1000 jars. how do you find out with only 10 rats?
|
Well, I assumed that if you gave the time limit and the time to die that they would be used...
|
+ Show Spoiler +Does the poison take exactly 2 hours to kill a rat?
If so, give a dose from a different jar each 3.6 seconds to the same rat. See when it dies, substract 2 hours and you know exactly at what time it drank the poisoned milk.
I must admit this solution doesn't seem very feasible in a real situation... but nothing in the ridle says it is not =)
EDIT: ouch fuck, it does. Did I misread or was that the part that was edited in the OP?
|
@travis
+ Show Spoiler +
Let's say we represent every single jar in binary. This requires 10 binary digits (2^10 = 1024 > 1000). Each of the 10 rats corresponds to one of these digits.
After you have represented all your jars in binary, you take your first rat, and feed it milk from all the jars that has a 1 in the first digit. Take the second rat, and feed it milk from all the jars that has a 1 in the second digit. Do this for all 10 rats.
The number 50 in binary is 0000110010. Each digit of the 10 digit binary number corresponds to one of the 10 rats, so you will feed the 2nd, 5th, and 6th rat some milk from the 50th jar. After 2 hours, these three rats will die, and you will know that it had to be the 50th jar, because no other jar had exactly these 3 rats drink from it.
|
|
|
|
|
|
EPT
