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ksk h2o
03-13-2002, 01:06 PM
Imagine you are in a room with no windows and the sole door is locked, on the floor is a lighter and two identical ropes. The ropes are identical but have a non-linear burn rate.  If one entire rope burns in one hour. how would you measue a slice of time of 30 mins?
Cero
03-13-2002, 01:27 PM
Wait till half the rope is burned i guess
Edea
03-13-2002, 01:33 PM
Wouldn't you get a bit low on oxygen if a rope was burning and there were no windows or anything.  http://www.emuxhaven.net/iB_html/non-cgi/emoticons/confused.gif
ksk h2o
03-13-2002, 02:19 PM
ehehe... okay we'll add a nice ventilation duct, and AC control dial, and a window to a sunny beach to the room...

cero: nah, the burn rate of the rope is non-linear and you do not know it, meaning half the rope could burn in twenty minutes, ten minutes, fifty minutes, etc.  Some parts burn faster and some parts burn slower, but you don't know which parts these are and at what rate they burn...

I think this just made it sound too complicated than it is but hey....
brightman
03-13-2002, 08:00 PM
*head about to explode thinking about this problem*

ok, maybe i am thinking too hard. Can you elaborate on what "a slice of time of 30 mins" means?
ksk h2o
03-14-2002, 05:54 AM
kind of like measuring 30 mins with a chronometer...  

you have to know when 30 minutes have elapsed but only have these ropes to meaure time, no chornometer.
The Tick
03-20-2002, 06:37 AM
What i don't get, is what the room has to do with the ropes?
ksk h2o
04-01-2002, 05:07 AM
I guess it's there to let you know that you can only use the ropes to tell time... you can't walk up to a guy on the street and beat him silly untill you take his watch and chono the thing...  you're confined in this space with only two ropes and you have to measure when 30 mins went by....


should I post the answer... does anyone still care?
brightman
04-01-2002, 09:15 AM
Sure, post the answer...
ksk h2o
04-04-2002, 04:11 AM
:::steady drum roll:::

You need to light one of the ropes at both ends.  Only if the rope is ingnited on both ends will it burn up entirely in 30 mins instead of 60.  Otherwise since the burn rate is linear there is no way of knowing how much time has passed by looking at the zise of the rope that remains unburnt.

So the second rope, the room all the rest are quite useless and provided for 'ambiance'