~The BrAiN tEaSeR Thread~

[TNC9852002]

Cut one of the ropes in half and then burn them.

Hmmmm, but I guess you said that there's no uniform burn, though...

-TNC

 

[Ahura Mazda]

Cut one of the ropes in half and then burn them.

Hmmmm, but I guess you said that there's no uniform burn, though...

-TNC

You answerred yourself. As they do not burn uniformly, length does not equal time.

 

[November Rain]

Here is another riddle.

You have 2 peices of rope which will each burn in exactly 30 minutes. However, there is no correlation betwen the two ropes and they do not burn uniformly. Therefore 1/4 of the rope could burn in 28 minutes and the rest in 2 minutes.

So how do you tell using the ropes and a lighter when 45 minutes have passed?

set one completely alight...

wait for it to finish, then set the other one alight on both ends

 

[Ahura Mazda]

Ok that is correct.

Now imagine the ropes burn in 60 minutes and not 30.

 

[November Rain]

so that's two ropes that burn for an hour and we half to know when 45 minutes passes right?

 

[Ahura Mazda]

so that's two ropes that burn for an hour and we have to know when 45 minutes passes right?

Exactly

 

[November Rain]

set on alight from both ends to get 30 mins...

then set the next one alight at both ends and also in teh middle to get the remainding 15 mins perhaps?

 

[Ahura Mazda]

set on alight from both ends to get 30 mins...

then set the next one alight at both ends and also in teh middle to get the remainding 15 mins perhaps?

That does not work because you do not know where the middle is given the length does not equal time principle.

 

[November Rain]

why not cut the second rope in half. burn one section at both ends, wait then burn the other section at both ends.

 

[Ahura Mazda]

why not cut the second rope in half. burn one section at both ends, wait then burn the other section at both ends.

No cutting - they are made of some material you cannot cut but you can burn.

Plus again half is meaningless given length does not equal time.

 

[November Rain]

i don't know if this will work but

if you start burning both ropes at the same time but rope number one is on fire from both sides....then when one burns out, then start burning the other side of rope numero two?

 

[Ahura Mazda]

i don't know if this will work but

if you start burning both ropes at the same time but rope number one is on fire from both sides....then when one burns out, then start burning the other side of rope numero two?

That is correct. Well done.

 

[November Rain]

based on the simplicity of their only being two ropes, there are only so many different things one can do with that type of puzzle.

that's a nice sized brain teaser...

 

[Carcharodon]

Riddle 71: The Gameshow*

You are on a gameshow. You have three doors to choose from (numbers 1, 2 and 3). Behind two of these doors are donkeys (one per door), and behind the remaining door is a brand new car.

You pick one of the doors, and it remains closed. The host then opens one of the donkey-doors, leaving two closed doors. This means that one of the doors conceals a donkey, and the other a car. You are given the opportunity to either stick with your initial choice or switch.

To get the car, do you stick with the initial door or do you switch, and why?

*If you've ever answered this question before or simply know the answer, please don't respond; it's a common question among statistics students.

 

[wiegeabo]

I'm going to let someone else answer this. I've been through it a few times.

 

[Majik1387]

You stick with it, because it's not like your odds have changed. It's still a 1/3 shot.

 

[Carcharodon]

I'm going to let someone else answer this. I've been through it a few times.

Hell, I've argued over this with people (and I was right). It's hard to wrap your mind around at first. Same principle with Deal or No Deal, actually. A very cool concept.

 

[Carcharodon]

You stick with it, because it's not like your odds have changed. It's still a 1/3 shot.

Here's something I didn't anticipate. I have to give away part of the answer.

No.

 

[Majik1387]

Here's something I didn't anticipate. I have to give away part of the answer.

No.

Fine then!

 

[Carcharodon]

Fine then!

I got assigned this in a math class...I was the only one in the class to actually solve it, but it's because I'm obsessive. This is a damn tough problem. I answered as you did at first.

 

[Dark Phantom]

ummmm...it doesn't matter. You'll lose either way.

 

[wiegeabo]

ummmm...it doesn't matter. You'll lose either way.

...wait, what?

 

[Dark Phantom]

...wait, what?

the one about the donkey doors and the car. I'm just trying to think of the most unlikely trick answer.

i mean the answer can't be "inital choice" or "switch". It has to be something no one would think.

 

[Carcharodon]

the one about the donkey doors and the car. I'm just trying to think of the most unlikely trick answer.

i mean the answer can't be "inital choice" or "switch". It has to be something no one would think.

No, it's one of the two choices. You just have to explain why.

 

[Ahura Mazda]

Switch because when you first choose you had a 1/3 in chance, but by switching you have a 1/2 chance....