The worlds first riddle!

Re: cannibal problem


maybe i must note that R is the only cannibal rower!!

the spy
myownusername your good @ logical puzzles so try figure this one out


the judge settled down. in front of him were three persons named A, B and C. one of them was a wanted spy. the judge was known by the fact that one of the persons always told the truth, the other always lied and the spy could tell the truth or tell lies. So the judge asks to A: 'are you the spy?' and A answered with yes or no. then the judge asked B if A was telling the truth and B answered also with yes or now. then A said that C wasn't the spy. The judge said that he knew that and he arrested the spy who was the spy?? A B or C?

Try

I have a small puzzle for you

You wrote:
"Five ants are on the corners of an equilateral PENTAGON with side of length 1. They each crawl directly towards the next ant, all at the same speed and travelling in the same orientation".

But you also wrote:
"It is intuitive that at all times the ants will form the corners of a SQUARE, ever decreasing in size and rotating about the centre".

Now it could be that my intuition and your intuition do not work the same. but I would find intuitive that the ants would form a rotating and ever-decreasing PENTAGON if that is how they started out and every ant moves exactly the same as any other.

Are you sure that you have not mixed up two puzzles - square and pentagon? Or a typo or something?

I have 'personal message'-ed three replies to you - square, pentagon, and a 'general rule for all polygons'.

Magnum and MyOwn

It seems to me that you have dealt with every possibility in the 'cannibals and missionaries' question. I see that not much gets past you guys and I look forward to competing with you

You have to keep a careful watch on Try. Sometimes he slips in a little 'mistake' just to see if everyone is still awake :wink:

Well, little problem is that english is not my native language so sometimes I am not sure if something means this what I mean it means

If: "then A said that C wasn't the spy. The judge said that he knew that" means that judge knows that C is not spy, and it certainly looks this way, then C is, obviusly not spy.

Then, we also know that A is not liar, because he told truth that C is not spy. So, B still can be everything, but A can only be spy or truth teller.

So...if A said Yes, and B said Yes, only possibility in that case is that A is spy (because if truth teller he wouldn't say Yes) - and in that case B is truth teller

if A said Yes and B said No, A still has to be spy, and then B can be liar

if A said No, however, then there are two possibilities...since he told truth about C, he can be either truth teller or spy - so if A=No and B=No, then A can be spy and B truth teller and A can be truth teller and B spy.
If A=No and B=Yes, then A can be truth teller and B spy, and A can be spy and B truth teller. (Edit: actually B is liar in that case but it remains same)

So, the way task is given I guess judge is smart man, so in this case he would not make any assumptions - simply, if A said "no" then judge cannot have clue who is spy.

Therefore it must be that A said yes, and he is spy.

Iacomus, glad to be here as well - however, as I said to Try, I'll skip tasks that require lot math formulas

MyOwn

You need not worry about the math. The 'ants' question was a bit 'unusual'.


A neat answer to the spy question. But a very strange spy, I think. The first question he is asked is 'are you the spy?' and he says 'yes I am' Then, without being asked he says 'and C is not the spy'. If he had said 'no' they could not have caught him. This spy was not very hard to catch.

yeah, pretty lousy spy hehe

as for C-M crossing river question, whoever posted it probably know answer? I mean, if its from some book or something like that - and if you think that all ideas are given, maybe "author" can post real answer?

The spy
About the spy question, look at this possibility:

A tells the truth, B is the spy en C is the liar.

A answers the first question with yes
B will say no to his question
and then A says that C is not the spy which is also the truth

why isn't B the spy????? explain to me if you can??

because if A is truth teller he would NEVER answer "Yes" to a question "Are you a spy?" (because, he is truth teller, not spy)

sorry my fault

it has to be this

A will answer no
B could still say yes or no
and A is also telling the truth about C

because in that case there are TWO options, so judge cannot decide for sure - if A said Yes judge can decide because there is only one possibility

in this case, if A says No, B says No there are two options: A can be spy and B truth teller AND ALSO A can be truth teller and B spy

if A says No, and B says Yes, again: A can be spy and B liar AND ALSO A can be truth teller and B spy.

So, in those cases judge can't say because those two possibilities can both be true and in every one of them another person is spy.
While, when A says Yes he must be spy (he is not liar because he said truth about C, and he is not truth teller because he would never say "Yes" in that case)

so, basically, there is GENERAL possibility that B is spy, but if B is spy judge is absolutely unable to know that for sure - so part that says that judge decided only according to their answers is also clue

New riddle
three men are blindfolded and they all get a green or a red hat. when the blindfold goes off, they must raise their hands if they can see a green hat ( they can't see their own ). Everyone raises their hand. A man is not allowed to lower his hand until he knows what color hat he is wearing.

After some time one man lowered his hand. What does he know???

are you sure you provided enough information? I don't think so, honestly.
The problem is that it seems there are more possible solutions, or, two of them should know colour of their hats, so maybe one of them is just smarter? But, that's very shaky then because in further developments other solutions are available as well...

First of all, let's eliminate things that are not possible:
a) 3R and B) 2R and 1G - those are not possible because in those cases not everyone would raise hand

c) if they all have green hats then every single one of them thinks that at least two of them have to have green hat (because if only one would have it, then he wouldn't raise hand, seeing only red on heads of two others)...and it still can't help them, because they cannot know which one is on their head...

so, it has to be:

d) 2 G and 1 R
and then...

1) the one with red hat sees two greens, so he can still have both colours on his head
b) those that have green see one red and one green - therefore, they know that they cannot possibly have red - because if they would have red too, then one they see with the green hat would see two reds and therefore he wouldn't raised hand at first place

BUT, in this case two of them can come to a clue that they have green hat...so we should probably assume that one of them is smarter?

After his release on bail, a leading supporter of the WMC said, "We urgently need funds to continue the fight for justice, against the faceless corporations.
From the 69th floor of his luxury office in the Able two No building one of the many executives said, "I wish them luck, but I wouldn't want to bet on it".

•176.016
• You are given $250 in promotional roulette chips. You may play roulette as long as you like but may only keep his winnings above the initial $250. You also may only play the even money bets like red and black. You also may only bet $10 at a time. With two zeros on the wheel the probability of winning any given bet is 20/38. What should your strategy be to maximize your expected winnings and what is the most you can expect to win


Following a request for an encryption question.

A clever, but financially strapped college student discovered that he had spent all of his room and board money on less academic pursuits. Quickly, he telegrammed his dear old parents for cash. However, he was so destitute, he could only afford three words. By an amazingly serendipitous stroke of fortune, he was able to send his request, the total amount needed, and the breakdown in this simple message:


...SEND
+ MORE
---------
.MONEY

How much did the poor student need, and how much were the two portions for room and board

Oh no, not the hats again. They caused my last 'problem'.

well, I am anxious to hear more about it

The start of my decline.

A merchant was hiring an assistant, and two young men showed up for the job. The trader said: "Let's see which of you two is the smarter."
He took the two boys into a room, took out a box, and said: "There are five hats in this box, two red, three black. And this is what we'll do: I turn off the light, and each of us three pick a hat from the box and put on one's own head. I then close the box, turn on the light, and let's see which of you two can be the first to tell me the color of the hat that is on your own head."

Actually the merchant did not tell the whole truth. Yes there were five hats in the box, but only one of them is red and the merchant knew how to get that red hat for himself. The two young men, however, did not know this and they believed what they were told: there were five hats, two red and three black.

The light was turned out, and each of the three picked a hat to put on. When the light was back on, the two young men saw a red hat on the merchant's head. They then looked at each other, but for a second neither of the two could tell what hat he himself was wearing. Finally, one of them cried out: "I know! I know!"

He got it right. Now, how did he figure it out