Riddles

[Kintsugi]

This is for all those who have good riddles to tell, those who wish to solve riddles but cannot compete in the Brain Teaser Competition (because they are staff or have won, etc.)

There are no prizes, so please do not cheat or answer if you have solved this in the past.

Please add more riddles! I will try to do one a week at least.

This one is for Anthony especially!

Format changed a little for sensitivity towards our combat members.

A two-parter:

The warm-up/part one:

You and 99 other people are captured by goblins. The goblins tell you all that you are going to play a game. The game is that they are going to place either a black or a white hat on each of you. There is no set ratio (99 white, 1 black, 50/50--not predictable at all). Everyone will be able to see each other, but no one can see their own hat. The goblins will ask each individual, moving clockwise around the circle of people, what color their hat is. If you get it right, you live. If you get it wrong, you die. You must only either say "white" or "black." No other signals can be given. No cues. Nothing. Just answering black or white. This is a logic problem, not a trick.

You all get a little time alone amongst yourselves to plan. Everyone in the circle is willing to be totally altruistic. Then they cover your faces, put on the hats, sit you in the circle and begin.

How do you ensure that 50 people have a 100% chance of survival and the other 50 have a 50% chance?

Part two, the real deal:
Ensure that 99 people have a 100% chance of survival and 1 person has a 50% chance of survival.

 

[KP the nut]

I am not logical, panic setting in, I can't even get the words in order.

Great thread though

 

[Kintsugi]

I am not logical, panic setting in, I can't even get the words in order.

Gosh, I don't want to inspire panic.

If it makes you feel any better, KP, the friend who told me this riddle said that it usually takes people weeks or months to crack this unless they have a strong math background. Though he said people with PhDs he's asked usually solve it within the hour. I asked a bunch of people at Waffle House at like 3am. One of them is very good at math and was able to crack it, but his explanation confused everyone else. >.<

 

[KP the nut]

Gosh, I don't want to inspire panic.>.<

Not your issue. Mine. I think it is great you're adding to these. I will always read them. But like 'sniglets' I'm lurking on the outside.

This is for the clever kids:roflmao:

 

[Kintsugi]

Guesses are welcome and may get you closer to the answer. I cycled through about 10 options (asking the riddle-giver) before I got to the solution for the first part. And it's helpful to do them separately, not feel pressured to do both at once.

 

[freakofnurture]

I know this riddle, but only with three persons wearing hats. So I have no idea how to do the thing with the ratios.

 

[Kintsugi]

So I have no idea how to do the thing with the ratios.

No ratios matter in the answer. There is no set ratio between the hats.

I suggest you start on the first part. It fires up your thinking for the next part.

 

[freakofnurture]

I suggest you start on the first part. It fires up your thinking for the next part.

I'll try.

My favorite riddle - though I'm sure most people know it:

Scenario: You are sitting in a boat in the middle of a lake. In your hands you hold a cannon ball. You drop the ball out of the boat.

Question: Does the level of the lake rise or fall now? Explain your answer.

 

[KP the nut]

Scenario: You are sitting in a boat in the middle of a lake. In your hands you hold a cannon ball. You drop the ball out of the boat.

Question: Does the level of the lake rise or fall now? Explain your answer.

The boat will rise as there is less weight in it, which will give the illusion of the water falling

 

[anthony]

How do you ensure that 50 people have a 100% chance of survival and Ensure that 99 people have a 100% chance of survival and 1 person has a 50% chance of survival.

The last person would see everyone else's hat. So he would say "black" if there are an odd number of black hats that he sees. The answer "white" will mean that there are an odd number of white hats that he sees.

At this time guy #99 will either be wearing a white or a black hat. If he is wearing a white hat he will only see an even number of white hats, and since guy #100 said that there is an odd number of white hats, guy #99 will know that he is wearing white and will say it. But if guy #99 is wearing a black hat, he will see an odd number of white hats (just like #100 did), and thus will know that he is wearing a black hat and will say it. No matter what #99 answers, guy #98 (who heard guy #100 and guy #99) can now easily incorporate the color of hat on guy #99 into the original answer of guy #100. This will allow #98 to know if he should see an odd or even number of white hats in front of him to determine his own hat color. The same thing repeats.

The first person to answer would get a 50/50 because of his role in the survival of the rest of them. He could get lucky.

 

[Nicolette]

Are you allowed to put your hat on the goblin asking the question so you can then see the color of your hat?

 

[Kintsugi]

Well done, Anthony. I don't have an account upgrade for you. : ( I could send you and Nicolette digital cookies.