Jump to content
BrainDen.com - Brain Teasers

Castle


rookie1ja
 Share

Recommended Posts

  • 2 weeks later...
  • 3 weeks later...

OK, you guys are ridiculous with your lashing, draining, and jumping. The problem should have stated that the conquerors only had 2 pieces of plank, each 9.5 m long. This is an easy puzzle, but I am impressed with some of the ingenuity. I see the last poster is the only one who got it right.

Link to comment
Share on other sites

For all you swimmers.. Maybe the moat is 20 meters deep and filled with sharks that have friggin' laser beams attached to their heads.

In that case, we could build a large wooden rabbit and leave it by the front door. When the French lower the gate and bring the gift inside, Lancelot and I would jump out, not only catching the French by surprise, but totally unarmed!

..or if we go with the wandering kids analogy: They found just two planks that were cut to 9.5 meters length and wanted to build their bridge to Terebithia over a 10 meter moat filled with leaches and nasty water that only that kid with greasy hair who sits in the back of the class picking his nose would even think of swimming in.

In this case, they would find a flimsy old rope hanging from a nearby tree and swing across with no explainable way of returning (although they always did). One of the kids would eventually die in this endeavor while the other was off carousing with his music teacher.

Link to comment
Share on other sites

You could just set up a village around the castle. Eventually the people in the castle will have to come out. They're going to need to come out for fresh water within a week easy.

This answer reminded me of the movie Kagemusha by Akira Kurosawa. Not necessarily...they might not have to come out.

Link to comment
Share on other sites

  • 4 weeks later...
First, about the post above mine, I don't know if I'm overlooking something, but why do you say 8.5 unit thength of bridge is being used to complete the diagonal bridge when the bridges are 9.5 and not 8.5 meters long?

Oooh, that's a simple one... A board of 9.5 metres length can not bridges a 9.5 metres moat, if it can't firmly rest on something like solid ground, can it? The assumption was therefor, that 1 metre of the board rested on the ground or on another board, probably 0.5 metres on either side

BoilingOil

Link to comment
Share on other sites

I would just put 1 bridge across the corner and the other from the middle of that bridge the edge of the island.

that's what's on the solution up top, you didn't need to put that on here.

Link to comment
Share on other sites

I didn't get where it said how wide the foot bridge could be... If it was 4m wide, then you put the plank at a diagonal, it would touch and you can cross between the opposite points of the plank.

a 9.5m long x 4m wide is 10.3m from corner to corner.

Link to comment
Share on other sites

  • 3 weeks later...

let's say it IS an army and not just any army it the DA from JK Rowling's 5th Harry Potter book they could just use magic. I know that can't happen but if it were a normal army half jumps the .5 meters left (the ones who are good at track) the other half stand on the other side of the bridge so it stays on land. The half that don't attack the castle keep watch on case the castle has an ali on land and they make sure the ali dosen't get into the castle.

Link to comment
Share on other sites

  • 2 weeks later...

The calculation is correct and this solution would work, IF and only IF the bridge was really thin. But, unless the people are tightrope walkers, you would probably assume the bridge is maybe a half meter thick. If that is the case, then you would have to move the angled bridge (the first one) half a meter in towards the corner. Otherwise, you would not be able to secure both sides of the width on the land. And if you don't secure the two ends, then it won't support the the second bridge. Also, if both sides of the width aren't secured, then the bridge wont stay flat, and you wouldn't be able to walk on it anyway. Unless we are dealing with an army of tightrope walkers.

Link to comment
Share on other sites

The calculation is correct and this solution would work, IF and only IF the bridge was really thin. But, unless the people are tightrope walkers, you would probably assume the bridge is maybe a half meter thick. If that is the case, then you would have to move the angled bridge (the first one) half a meter in towards the corner. Otherwise, you would not be able to secure both sides of the width on the land. And if you don't secure the two ends, then it won't support the the second bridge. Also, if both sides of the width aren't secured, then the bridge wont stay flat, and you wouldn't be able to walk on it anyway. Unless we are dealing with an army of tightrope walkers.

right

Link to comment
Share on other sites

The calculation is correct and this solution would work, IF and only IF the bridge was really thin. But, unless the people are tightrope walkers, you would probably assume the bridge is maybe a half meter thick. If that is the case, then you would have to move the angled bridge (the first one) half a meter in towards the corner. Otherwise, you would not be able to secure both sides of the width on the land. And if you don't secure the two ends, then it won't support the the second bridge. Also, if both sides of the width aren't secured, then the bridge wont stay flat, and you wouldn't be able to walk on it anyway. Unless we are dealing with an army of tightrope walkers.

for anyone who wants to see the calculations:

laying the 9.5 m bridge across the corner, at 45degree angles to the edge of the moat, gets you 4.75m out: from the corner of the moat to the left edge of the bridge, regardless of the thickness of the bridge, assuming that the corners on the left edge of bridge are sitting on land.

the distance we're trying to span is 14.1 or 14.14 (the square root of 200). 14.14 - 4.75 = 9.39. if you lay another 9.5 m bridge over that gap, then you have .11 meters of excess which equates to .055 m on each end (2 inches?). the end that crosses the moat is laying on a corner. you wouldn't want its corners hanging over the edge of the moat, otherwise you'd have a very unsturdy path. since .055 m are laying on land, you wouldn't want it to be any wider than .011 m (hopfully you guys understand triangles. i'm too lazy to draw a diagram). so this army is basically walking on 4-inch wide bridges. watch out for the sharks...

but it works and it's ingenious. laying a third bridge on the outside corner of the moat to the bridge placed diagonally will give you some extra breathing room. rookie showed that in his solution too.

for all those people talking about running and jumping, can you image how much a 30ft bridge weighs? mechanically, there's no way you could have people standing on one end, the other hanging over the gap, and have people trying to run and jump the difference. the puzzle says a wise man came up with a solution, not a guy from Jackass =)

Link to comment
Share on other sites

The calculation is correct and this solution would work, IF and only IF the bridge was really thin. But, unless the people are tightrope walkers, you would probably assume the bridge is maybe a half meter thick. If that is the case, then you would have to move the angled bridge (the first one) half a meter in towards the corner. Otherwise, you would not be able to secure both sides of the width on the land. And if you don't secure the two ends, then it won't support the the second bridge. Also, if both sides of the width aren't secured, then the bridge wont stay flat, and you wouldn't be able to walk on it anyway. Unless we are dealing with an army of tightrope walkers.

It wouldn't matter how thin the bridge is. The left edge will ALWAYS be 9.5m. If it were a thin bridge, it will STILL be 9.5m. Thus, it can span the same distance as the thin bridge with the right side also resting firmly on dry ground.

Link to comment
Share on other sites

The calculation is correct and this solution would work, IF and only IF the bridge was really thin. But, unless the people are tightrope walkers, you would probably assume the bridge is maybe a half meter thick. If that is the case, then you would have to move the angled bridge (the first one) half a meter in towards the corner. Otherwise, you would not be able to secure both sides of the width on the land. And if you don't secure the two ends, then it won't support the the second bridge. Also, if both sides of the width aren't secured, then the bridge wont stay flat, and you wouldn't be able to walk on it anyway. Unless we are dealing with an army of tightrope walkers.

It wouldn't matter how thin the bridge is. The left edge will ALWAYS be 9.5m. If it were a thin bridge, it will STILL be 9.5m. Thus, it can span the same distance as the thin bridge with the right side also resting firmly on dry ground.

stability of bridge was questioned (and joelbernardo03 did some math on that) ... see picture below for better understanding

post-2-1193951485_thumbgif

Link to comment
Share on other sites

Yeah, all I was saying is that it doesn't matter about the width regardless of the math. I've demonstrated below. All the proportions are equal, so this should give you a good idea of what I'm talking about.

BridgeDemo.jpg[/attachment:7cb7b]

If the leading edge of both bridges is 9.5 meters, then both bridges can go the same amount of distance away from the corner as demonstrated above. Both bridges are the same length. The only different stat in the whole picture is the width of either bridge.

post-2497-1193953387_thumbjpg

Link to comment
Share on other sites

What if you put on board a full foot off the lege, then placed the second board on top of the first one that is sticking out a little, and thus make the gap to the castle. All you wold need is a few people standing on the board that is mostly on the ground (only has a foot peaking over the edge). Would that work?

Link to comment
Share on other sites

Yeah, all I was saying is that it doesn't matter about the width regardless of the math. I've demonstrated below. All the proportions are equal, so this should give you a good idea of what I'm talking about.

post-2-1174937043_thumbpngBridgeDemo.jpg[/attachment:82794]

If the leading edge of both bridges is 9.5 meters, then both bridges can go the same amount of distance away from the corner as demonstrated above. Both bridges are the same length. The only different stat in the whole picture is the width of either bridge.

absolutely correct, but assuming all the bridges they build are identical in width, you'd have a problem when you place the second bridge. in the picture below, you can see how the excess would be hanging over the edges and be very unsteady. the picture doesn't really do it justice. when you break down the numbers, the second bridge barely reaches the other side, only by a few inches. put a one meter wide bridge on a corner that is only 4 inches wide and you can imagine how wobbly it would be.

post-903-1194467849_thumbjpg

Link to comment
Share on other sites

Doi; Just follow these instructions.

#You do not have extra support, so several people can fall back and hold the bridge down. Then everyone can cross one by one, then jump the remainder of the moat. When they are out of people (besides the bridgeholders) the bridgeholders cross 1 by 1, starting with the lightest, and ending with the heaviest making a run for it...

Not nearly as complicated as the admin's solution.

Link to comment
Share on other sites

So I thought of overlaying them underwater for support... there is nothing on depth.. so one could assume to attempt this solution and it will be successful as long as the depth is < ~8.5 - 9 met ers... for cushion on the bottom...

post-2755-1195066119_thumbjpg

Link to comment
Share on other sites

All of these answers are wrong. The right way to do it is to outfit the conquering nation's warriors in tangerine speedos and have them do flagrant calisthenics in the morning. The defending warrior's laughter will render them defenseless. Then, light some stuff and throw it at the castle. The defending castle will be vanquished and surrender out of general principle. After all, who would want to live in a freakin square castle with a morning view of men in tight outfits? Not me.

Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...