An Easy Rope Problem

[bri bri]

Here's the problem:

You are a thief. A rich person has interwoven strands of
gold within two ropes. The ropes hang one foot apart from each
other in a fifty foot high room. They are attached firmly to the
ceiling with a very strong glue. The ropes are both fifty feet
long. The closest walls to the ropes are a long long way away.
You have a pair of scissors.

You want to steal as much of the two ropes as possible.
However, if you drop from more than ten feet above the floor, you
will break both of your legs.

How much of the two ropes can you steal? (Without breaking
your legs.)

It's more than 60 feet.

(Assume you aren't a mountaineer, and don't know how to tie
complicated things like slip-knots...)

[David Karr]

The question was how much of two 50-ft hanging ropes you can steal.
(SPOILER follows)

Call the ropes A and B. Tie them together at the bottom. Now climb up
to the ceiling. Cut rope A about a foot from the ceiling, and tie rope B
(now 99 ft long including the part that used to belong to A) around your
waist as close to the ceiling as possible. Tie a loop in the end of
rope A and pass the end of rope B through it. Continue pulling the
rope through (about 90 ft) until you are supported by the part of B that
goes through the loop rather than the part attached to the ceiling.
Now cut rope B right at the ceiling. Using the loop of A as a pulley,
lower yourself to the floor. If you haven't wasted any rope, you should
have at least 78 feet of rope B to play with, which will get you within
10 feet of the floor so you can drop safely and get away with 99 feet
of rope.

[Dave Munroe]

In article <30...@sdcc12.ucsd.edu> bdu...@sdcc13.ucsd.edu (bri bri) writes:

> How much of the two ropes can you steal? (Without breaking
>your legs.)
>
> It's more than 60 feet.


Somewhat unorthodox: climb a rope to the top, cut the other rope, giving
you 50 feet. Go down, coil the cut rope beneath the first rope (let's say
this gives you a "platform" 1 foot high). Climb the first rope again to
10 feet above the coiled rope, cut your rope and fall down on the coil. In
this example, you'd get 50+10+1 = 61 feet.

-Dave

[Matthew T. Russotto]

In article <30...@sdcc12.ucsd.edu> bdu...@sdcc13.ucsd.edu (bri bri) writes:
>

I'll learn!

Here's how I do it, but you might not like it:

Climb to the top of one rope. Grab the other rope and tie it so there
is a loop in it big enough to pass another rope, but not a knot. Cut
it off below the loop (but don't drop the cut off section!). Tie the
cut off section to the rope you are hanging on to. Thread that
through the loop. Grab that rope, and cut the one you are on, above
the knot (which is now held by the loop). Climb down the rope you are
hanging on (unless you can't tie a knot to save your life, you won't
break your legs), grab the other segment, and pull your 90+ feet of
booty out.

--
Matthew T. Russotto russ...@eng.umd.edu russ...@wam.umd.edu
Some news readers expect "Disclaimer:" here.
Just say NO to police searches and seizures. Make them use force.
(not responsible for bodily harm resulting from following above advice)

[Joseph William DeVincentis]

Climb to the top. Tie the two ropes together close to the ceiling.
Cut one rope just below the knot, and tie the piece to the other
rope just below the first knot, and throw the long end through the
loop you created with your first knot. Now, hanging from the loop, cut
the second rope between the two knots. Now you have two short ropes
hanging from the ceiling with their ends in a knot, and a two long ropes
tied together at one end hanging from the first rope. Climb down, and pull
the long rope free. You escape with almost 99 feet of rope (99 feet less
whatever amount is needed to make the knot.

--
\ Joseph De Vincentis jw...@owlnet.rice.edu /
\ Go Rice! Trevor Cobb for Heisman in 1992!!! /
\ Rice vs. UT: 103-97 Go Rice! /
`------------------------------------------------------------'

[Warwick Allison]

In <30...@sdcc12.ucsd.edu> bdu...@sdcc13.ucsd.edu (bri bri) writes:

> You want to steal as much of the two ropes as possible.

Climb rope A, and cut off B right at the ceiling, then tie it to the very top
of A. Now, tie a granny knot in B, but have the loop go through the finger
rings of the scissors. Place the blades of the scissors over both ropes
(depending on the thicknesses of the ropes and the shape of the scissors, you
may need to leave some of B glued in place to use as a support for this bit).
Then, climb down A, and pull hard on B, cutting both ropes, and achieving
almost 100% of the ropes.

Warwick.
--
_-_|\ war...@cs.uq.oz.au / enosis eosins /
/ * <-- Computer Science Department, / essoin noesis /
\_.-._/ University of Queensland, / noises nosies /
v Brisbane, Australia. / ossein sonsie /

[Stein Kulseth FBA]

The question was how much of two 50-ft hanging ropes you can steal.
(SPOILER follows)

The standard solution to this problem is to use a foot of one rope to
tie a loop, then to lower yourself to the ground, using both ropes
tied together, put through the loop.

I hereby introduce the Infamous Scissor Knot, which should enable you
to get also that last foot of rope (save some inches). After cutting
one rope you use this to tie the ISK around the top of the other rope.

How to tie the ISK, (top view, crude ascii)

oooo oooo
o o ________ ooooo
<<-- o ---\oo / ooo\o
oooo \ /o oooo# \
\ oo ### |
oooo / \o oooo# /
o Xoo \ ooo/o
o o \______/ ooooo
oooo oooo

Legend:

ooo scissors
--- loose rope
# rope to be cut (top view, remember)
X secure knot to scissor handle
<< 50 foot loose end

Now tighten the knot by pulling the loose end (DON'T PULL TOO HARD YET,
just enough to keep the ISK from falling down). Climb down, pull the loose end
hard. The ISK will now cause the scissors to close, cutting the rope.

(Hopefully, that is :-)

--
Stein Kulseth
Norwegian Telecom Research, Box 83, N-2007 KJELLER, NORWAY
internet: st...@hal.nta.no X400: stein....@forskning.teledir.no
Phone: + 47 6 80 98 05 Fax: + 47 6 81 00 76

[Lisa Ehren]

bdu...@sdcc13.ucsd.edu (bri bri) writes:
> You are a thief. A rich person has interwoven strands of
> gold within two ropes. The ropes hang one foot apart from each
> other in a fifty foot high room. They are attached firmly to the
> ceiling with a very strong glue. The ropes are both fifty feet
> long. The closest walls to the ropes are a long long way away.
> You have a pair of scissors.
> You want to steal as much of the two ropes as possible.
> However, if you drop from more than ten feet above the floor, you
> will break both of your legs.

I'm new to this group, so let me know if this won't work...

You didn't say that you were locked in or anything, so obviously you can
get out. What about if you got a lighter and burned up the ropes thus b
burning off the glue and causing the gold to drop down...even if it did
melt, you could wait till it solidified and picked it up from the floor.

--
Fuzzies to you all.
-Latarra

If I am the only one who can be me, and I can only be me, if I am not me,
then am I nothing and is no one me?

[Karlon West]

I didn't see any other responses to this puzzle, but assuming all you have
is a knife and you are locked in the room, is there an answer that will get
you all the rope. I've come up with one that will get me all but about six
inches of rope.

Just curious.

kar...@bnr.ca