Steem Riddle of the Week #6: Burning Ropes (Prize Doubled)

in #life7 years ago (edited)

Riddle #6: Burning Ropes

Since no one claimed last weeks prize, I decided to double the prize for this week, see details at the bottom

This weeks riddle goes as follows:

You have two ropes. One rope takes exactly one hour to burn. The other rope takes exactly 10 minutes to burn. You have a reusable lighter. You must measure exactly 25 minutes. The ropes burn don't necessarily burn at a uniform rate, some parts of the rope burn quickly and others slowly, so you cannot guess when a certain percentage of the rope has been burned by measuring the length that has burned.

How can this be done?

Prize

This week, the first person to upvote and comment with a valid solution (as decided by me and only me) prior to 1-14-2017 midnight UTC will get a (doubled) 2 SBD prize! The prize will be paid out right after the rewards from the post are paid.

Don't forget to follow and to check out my past riddles

First off, thanks to everyone for all the support! If you'd like to browse my older riddles you can do so at the links below:

https://steemit.com/life/@droopy/steem-riddle-of-the-week-2-flipping-cards-prize-doubled
https://steemit.com/life/@droopy/steem-riddle-of-the-week-3-alternating-truth-prize-for-first-correct-answer
https://steemit.com/life/@droopy/steem-riddle-of-the-week-4-black-cards-prize-for-first-correct-answer
https://steemit.com/life/@droopy/steem-riddle-of-the-week-5-the-cup-game-prize-for-first-correct-answer

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Use the lighter to Burn both sides of the first rope and also the middle of the first rope.
If we would have lit up only both ends of first rope, it would have taken 30 min to fully burn the whole rope.
So, lighting up in the middle of the first rope will cut the time in half.

So, in 15 min, 1st rope will burn out.
Then we have to burn one end of 2nd rope. It will take 10 min.

So, in total, it will take 15 + 10 = 25 min :)

GLHF

I am the first to comment and hopefully the first one to give out the answer correctly :)

This would work if you could identify the exact middle of the one hour rope (in terms of time to burn, not in terms of length) but since the rope burns non-uniformly, you have no way to do this. The left half of the rope could take twice as long to burn as the right half. Great idea though.

I can't think of any more ideas. So, I give up :D
Could you please let me know the answer after this contest is finished ?

Of course :) I always post the solution the day that the contest ends, so just follow me and you'll get a notification when its posted :)

Of course. I will do so :)

Okay, so this is my answer
Let's say the rope that burn within an hour is rope A, and the rope that burns within 10minutes is rope B.
Set fire to both the ropes at the exact same time, then measure amount of rope A burnt when rope B is completely incinerated.
Cut that exact length of rope A out two and a half times. Then burn this length of rope, and that should be 25minutes...
This is what I could come up with

Rope A burns non-uniformly so some part of the rope might burn slower or faster than other parts. There is no way to measure a specific length and know that say, one half of the rope in length will take one half of the time to burn.

Ok I think I might have a solution! If you're able to do this.
You cut the first rope into 2 pieces(the 1 hour rope) and light both ends of both pieces. The moment one piece is burned completely you cut the remaining piece in half and light both ends continuing to do so until the first rope is burned completely, lighting one end of the second(10 minute rope) as the first rope finishes. This should make it so the first rope only takes 15 minutes.

If you don't want the ropes cut, you could simply light the middle of the remaining rope every time 2 burned ends meet.

Wow, that is not the solution that I had in mind, but I think it works, very nicely done! I'll ship you the prize within 24 hours of this post paying out :)

Awesome! Definitely took some pondering and glad to see it worked out!
Thanks for hosting these contests, they're a fun little break! Followed yah for the next one

Thank ye kindly good sir! Much appreciated!

This post has received a 0.79 % upvote from @booster thanks to: @droopy.

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