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Room on Stilts

  1. Jan 14, 2007 #1
    You are locked in a 50'x50'x50' room which is on 100' stilts. There is a small window near the floor on one side (too far from the stilts to reach), with a small hook embedded in the floor beside it.

    In the centre of the room hanging from the ceiling are two 50' ropes.

    You have no tools except a sharp knife, but are a good rope climber.

    How do you get out of the room?
  2. jcsd
  3. Jan 14, 2007 #2


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    I have to be good at tying knots too. :tongue:
  4. Jan 14, 2007 #3
    Yes, of course! I left that out.

    Thanks :wink:
  5. Jan 14, 2007 #4


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    Well, I know there's more to the "correct" answer than this, but this would work:

    Grab rope A, climb up rope B to the top and cut down as much of rope A as possible.

    Tie it off to the hook. Lower yourself down to the bottom of the rope, and start swinging. Swing till you reach the nearest stilt. Grab on.

    Gather up what rope you have left - you only need a 6 or 8 feet - and cut it. Use it to make a loop around yourself and tthe stilt. Inch your way down like a lumberjack.

    (I know that the trick to the puzzle is actually to tie a knot at the top of rope A then make a slipknot. You can manage to reach the floor with much more than 50 feet of rope. But I don't rmeember how it's done.)
  6. Jan 14, 2007 #5


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    See attached picture, in an equal-width font.

    Attached Files:

    • rope.txt
      File size:
      284 bytes
    Last edited: Jan 14, 2007
  7. Jan 15, 2007 #6


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    No can do. Permission denied.
  8. Jan 15, 2007 #7
    How are the ropes attached to the ceiling? If the ropes are independantly tied to (say) large hooks, then I can see how you might do it. If they're attached otherwise, it might be tricky. (Like if, say, they're glued to the ceiling)

    Also, I'm assuming that these ropes are sturdy enough to support your weight, BUT if you (for instance) start un-braiding the rope, it won't support your weight any more.

  9. Jan 16, 2007 #8
    A small bit of rope looped around the hook should be sufficient for me to grab onto as I hang out of the window and thus get out of the room. Do you want me to get to the ground too?
  10. Jan 16, 2007 #9


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    Uh, that's what the knife is for...
  11. Jan 16, 2007 #10
    How's this for a solution? Climb up rope A holding the end of rope A. At the top, cut off rope B (holding on to it) and tie the end of this roughly 40-45 foot protion of rope B to the end of rope A. Let rope A hang freely. Tie the remaining top portion of rope B into a strong loop (to support your weight). Pull rope A back up and thread it through the loop you just made in rope B, tieing the end of rope A to your waist just after threading through. Grab the portion of rope A that will let you hang from the loop in B and cut rope A as much as possible. Lower yourself to the floor (slowly). Once on the floor, you now have a roughly 90-95 foot piece of rope. Tie it to the hook and lower yourself down to the ground, and you only have to drop a few feet (90 - 95 feet of rope and you hang from the end means your feet dangle a few feet above the ground.
  12. Jan 16, 2007 #11
    Actually, it also says "You are locked in". Does that mean we can't open the window? If the problem is about ropes and getting down to the ground, why should we be "locked" in the room, rather than just be in the room? Further, what's the deal with the stilts? If the object of the problem is as I assume it is, it's got nothing to do with how the room is suspended at all, and stilts give you a *fantastic* escape route, as pointed out earlier. Why not say that the room is on a pedestal that's 50x50x100? That way even all our rope won't wrap around it. Or just say that the room is magically suspended in mid-air?

    I expect that the answer that he's looking for is as DaveC426913 implied (and maybe Hurkyl said, but I'll never know since I can't seem to see any attachments on these boards, ever):

    Call the ropes 1 and 2. Rope 1 has ends A and B, rope 2 has C and D. Assume A and C are glued to the top of the ceiling.

    Tie B to your waist, and start climbing rope 2. When at the top, cut off most of rope 1, but leave enough to tie a sturdy lasso/slip-knot, and do so. Now, untie B from your waist, and tie it to the new lasso. Switch and now hang on to rope 1 from B. Cut rope 2 off the ceiling at C, and tie A and C together (Ok, it's not really "end A" anymore, but you know what I mean). Pull up rope 2, and thread it through the lasso at end D. Switch to hold on to ropes 1 and 2 at the same time. Untie B from the lasso. Descend, effectively from A and C at the same time. Pull both ropes down through the lasso. You now have *most* of the rope. Tie one end of the rope to the hook in the floor, toss the rest out the window, and climb down to the ground.


    [edit]Doh! Looks like daveb posted the same thing. I had been waiting for a reply about how they're attached to the ceiling, thinking that perhaps you could thread the ropes through the attaching mechanism (if it was a hook or something), until I realized (as daveb did) that you could just loop through a piece of the rope instead...[/edit]
    Last edited: Jan 16, 2007
  13. Jan 16, 2007 #12


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    I can't see Hurkyl's attachment either, so I don't think it's just you: it says I don't have the privileges!
  14. Jan 16, 2007 #13
    Good solutions. I especially like DaveC426913's.

    Good question about the ropes. The ropes are cemented into the ceiling as well. Sorry I neglected to mention it. :wink:
  15. Jan 16, 2007 #14


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    Well, since some people can't seem to see my ASCII art, I'll risk the spoiler. :frown:

    Code (Text):
           /  |
          /   +
         /   / \
        /   /   \
        |  |     |
        +-----\  |
        |  |   \ |
        |   \   /
        |    \_/ \
        |        |
        \        /
         \      /
          \    /
           \  /
           |  |
           |  |
           :  :
           :  :
    I tried to diagram what you want to do with the rope. You can see that once you make the cut, you have most of the rope hanging in two strands through the loop, which conveniently can (nearly) reach the floor.
  16. Jan 17, 2007 #15
    just climb out the window....you'll probably plummet to your death but you'll be "out of the room"
  17. Mar 12, 2007 #16
    After cutting one rope off the ceiling, I would only bother with one rope, attach it to the hook, lower myself down (so now I'm a little more than 50' off the ground. Then I would swing over to one of the stilts, grab on, and slide down.
    Last edited: Mar 12, 2007
  18. Mar 12, 2007 #17


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    Honestly, swinging doesn't sound very easy! Unless I made a mistake in my calculation, with 50 feet of rope you'll have to be swinging at a speed of 14 miles per hour (at the lowest point) in order to have enough kinetic energy to reach one of the stilts!
  19. Mar 12, 2007 #18
    After drawing to scale- The farthest from the stilt I would be is 25'. So, 50' down, 25' over... about 30 degrees. I think I'd be able to manage it.
  20. Mar 12, 2007 #19
    How's this: Climb the ropes. At the top, holding on to both ropes at the same time (it says you're a skillful climber) carefully cut part of both of them so that your weight is still supported by both but not by only one of them. Climb down using both ropes to support your weight. At the bottom, hang from each rope one at a time to break them then tie them together into a 100' rope.
  21. Mar 12, 2007 #20
    Meh, that's not so bad. Sure, you'd be going fast at the lowest point, but at the highest point, you're at a nice, dead stop. Bigger worries would be:

    1) The rope fraying as it rubbed against the windowsill and/or bottom of the room

    2) Can you actually wrap your arms around the stilts in order to hold on sufficiently?

    3) Missing the stilts entirely, and instead swinging at an angle that's not parallel to the side of the room

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