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Main Forums => Homework Help => Topic started by: city_slick on February 09, 2009, 12:45:50 AM

Title: Math Survey
Post by: city_slick on February 09, 2009, 12:45:50 AM
I'm collecting some data for school and need data from as many people as possible. Thanks!

Who can solve this problem in one try without looking at the answer?:

There are two lengths of rope.
Each one can burn in exactly one hour.
They are not necessarily of the same length or width as each other.
They also are not of uniform width (may be wider in middle than on the end), thus burning half of the rope is not necessarily 1/2 hour.

By burning the ropes, how do you measure exactly 45 minutes worth of time?


Be honest! And be sure to leave a post saying whether or not you get it on the first try!

The answer can be found at http://mindcipher.com/puzzle/41-burning-rope (http://mindcipher.com/puzzle/41-burning-rope)

Thanks for your help!
Title: Re: Math Survey
Post by: Novice on February 09, 2009, 12:56:12 AM
16
Title: Re: Math Survey
Post by: ivan on February 09, 2009, 08:30:05 AM
Light the ropes on fire, then set a timer for 45 minutes.


Title: Re: Math Survey
Post by: Socrates on February 09, 2009, 10:03:50 AM
I'd say light one rope on fire, wait exactly 15 minutes then light the second rope on fire.

when the first rope burns out exactly 45 minutes have passed since you started the second rope.

Easy.
Title: Re: Math Survey
Post by: ivan on February 09, 2009, 10:39:37 AM
Excellent.
Title: Re: Math Survey
Post by: dcrog on February 09, 2009, 11:25:18 AM
I would simply use a clock.
Title: Re: Math Survey
Post by: BizB on February 09, 2009, 11:38:51 AM
It's really much more simple than that.

Fold the ropes in half.
Light the folded end of one of the ropes.
...
Profit
Title: Re: Math Survey
Post by: 12AX7 on February 09, 2009, 11:57:33 AM
Is this rope made from hemp?
Title: Re: Math Survey
Post by: Wunderkind on February 09, 2009, 05:26:20 PM
First, why the hell would you try to tell time by burning a rope?

Secondly, regardless of any of the contributing factors the answer will always be 42.

And lastly, 12 is right, along with various weather factors like windspeed and direction and humidity percentage, what the rope is made out of will effect how it burns.
Title: Re: Math Survey
Post by: whyny on February 14, 2009, 10:57:30 PM


Secondly, regardless of any of the contributing factors the answer will always be 42.


That's wisdom in the purest form.
Title: Re: Math Survey
Post by: h4wt_b3t4 on September 04, 2009, 09:50:09 PM
First, why the hell would you try to tell time by burning a rope?


Uhm... ditto. And I'm going to guess 135.
Title: Re: Math Survey
Post by: xolik on September 04, 2009, 10:00:40 PM
Uhm... ditto. And I'm going to guess 135.

See, I'm glad people bump threads that have been dead for over seven months. I totally missed this one!

Two pieces of string walk into a bar and the bartender looks at them suspiciously. He says "Sorry, boys, we don't serve your kind here." So the pieces of string walk out again.

They're sitting in the gutter outside and feeling really thirsty when one piece of string says "Hey! I've got an idea to get me into the bar."

So he starts twisting and turning, wriggling this way and that, pulling out a few threads here and there. His mate's looking at him and thinks he's gone completely nuts.

Then the piece of string walks back into the bar. The bartender looks at him a little suspiciously again and says "Here, you're not a bit of string, are you?"

The piece of string replies "No, I'm a frayed knot!"
Title: Re: Math Survey
Post by: h4wt_b3t4 on September 05, 2009, 04:14:15 AM
Haha, that was great. I must remember to suggest that for the joke of the day at the high school I go to... then again, since it has the word 'bar' in it, the administration will likely freak out and suspend Cole for telling that joke. (Every morning, during the announcements, this kid named Cole tells a joke of the day.)

Anyway, yeah, that was a good one.