## Riddles

For discussing anything related to physics, biology, chemistry, mathematics, and their practical applications.

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### Re: Riddles

Arminius wrote:Weekday.

Seven people, A, B, C, D, E, F, G discuss which weekday is today:

A: "The day after tomorrow is Wednesday."
B: "No, today is Wednesday."
C: "You both are wrong, Wednesday is tomorrow."
D: "Today is not Monday, not Tuesday, and not Wednesday."
E: "I am sure that yesterday was Thursday."
F: "No, yesterday was Tuesday."
G: "All I know is, that yesterday was not Saturday."
If only one statement is true, on which weekday was that conversation?

Sunday
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### Re: Riddles

incorrect wrote:
Arminius wrote:Two Children.

A boy and a girl are talking: "I am a boy", says the blond child. "I'm a girl", says the black-haired child. At least one of the children is lying.

What hair color does the girl have?

blond

You are correct, although your username is "incorrect".

incorrect wrote:
Arminius wrote:Weekday.

Seven people, A, B, C, D, E, F, G discuss which weekday is today:

A: "The day after tomorrow is Wednesday."
B: "No, today is Wednesday."
C: "You both are wrong, Wednesday is tomorrow."
D: "Today is not Monday, not Tuesday, and not Wednesday."
E: "I am sure that yesterday was Thursday."
F: "No, yesterday was Tuesday."
G: "All I know is, that yesterday was not Saturday."
If only one statement is true, on which weekday was that conversation?

Sunday

You are correct, although your username is "incorrect".

Arminius
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### Re: Riddles

Another try at the 100 pessimists

Each sentence invalidates itself, so at any given time, only 1 sentence is incorrect. So at end 99 correct, 1 wrong.

phoneutria
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### Re: Riddles

Arminius wrote:100 Pessimists.

100 pessimists have written 100 senntences on a sheet of paper. Each pessimist has written 1 sentence. The 100 sentences are numbered from 1 to 100. The first pessimist has written: "Exactly one sentence on this sheet is wrong.". The second pessimist has written: "Exactly two sentences on this sheet are wrong.". .... And so on. Which sentences are wrong, which right?

All of them are right

Hint
The first typo is something to pay attention to

Another hint
I like this one a lot
Last edited by Innovice on Tue Sep 22, 2015 2:40 am, edited 3 times in total.
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### Re: Riddles

Arminius wrote:Five persons A, B, C, D and E chat:
A: "B lies if and only if D is telling the truth."
B: "If C is telling the truth, then either A or D is a liar."
C: "E lies, and also A or B lie."
D: "If B is telling the truth, then A or C too."
E: "Among the persons A, C and D is at least one liar."
Two persons are lying. Which?

You are lying.

Rationale

A+E and B+E are two acceptable options. If only you are lying there are less liars.
Innovice
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### Re: Riddles

phoneutria wrote:Another try at the 100 pessimists

Each sentence invalidates itself, so at any given time, only 1 sentence is incorrect. So at end 99 correct, 1 wrong.

That is false.
Last edited by Arminius on Tue Sep 22, 2015 5:52 pm, edited 1 time in total.

Arminius
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### Re: Riddles

incorrect wrote:
Arminius wrote:100 Pessimists.

100 pessimists have written 100 senntences on a sheet of paper. Each pessimist has written 1 sentence. The 100 sentences are numbered from 1 to 100. The first pessimist has written: "Exactly one sentence on this sheet is wrong.". The second pessimist has written: "Exactly two sentences on this sheet are wrong.". .... And so on. Which sentences are wrong, which right?

All of them are right

Hint
The first typo is something to pay attention to

Another hint
I like this one a lot
incorrect wrote:
Arminius wrote:Five persons A, B, C, D and E chat:
A: "B lies if and only if D is telling the truth."
B: "If C is telling the truth, then either A or D is a liar."
C: "E lies, and also A or B lie."
D: "If B is telling the truth, then A or C too."
E: "Among the persons A, C and D is at least one liar."
Two persons are lying. Which?

You are lying.

Rationale

A+E and B+E are two acceptable options. If only you are lying there are less liars.

Incorrect, all your solutions are incorrect.

Arminius
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### Re: Riddles

but! you said it was correct grr

phoneutria
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### Re: Riddles

While reading I was influenced by my wishful thinking ( ), because I wished very much (too much!) that you solved the riddle. But, unfortunately, you did not solve the riddle, and I became sad.

Arminius
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### Re: Riddles

If a first reading fooled you, maybe I was close...
each sentence invalidates itself, therefore they are all false

phoneutria
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### Re: Riddles

phoneutria wrote:If a first reading fooled you, maybe I was close...
each sentence invalidates itself, therefore they are all false

No. Unfortunately no. Please try again.

Arminius
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### Re: Riddles

lol I was reading it wrong again

has to be 50-50

phoneutria
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### Re: Riddles

phoneutria wrote:If a first reading fooled you, maybe I was close...
each sentence invalidates itself, therefore they are all false

phoneutria wrote:lol I was reading it wrong again

has to be 50-50

Both answers are false.

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### Re: Riddles

i give up lol

nonono one more

dude 99 is correct

phoneutria
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### Re: Riddles

Hey, are you sure? You give up, Phoneutria?

phoneutria wrote:
phoneutria wrote:dude 99 is correct

Do you mean that the sentence of the 99th person is correct? And if so: Why is the sentence of the 99th person correct? And what about the other persons? Please give a rationale why the sentence of the 99th person is correct and what about the other persons and why.

Arminius
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### Re: Riddles

Yeah once I stopped abd thought about it out loud for a second, i felt pretty dumb for not figuring out before hehe

first I thought, there are only two possibilities. a single sentence being correcy, or none, because they are all mutually exclusive.
but then, if none are correct, dude 100 would be correct. but if dude 100 is correct, then there would be 99 wrong sentences. so he can't be correct.
if 1 sentence is correct and 99 are wrong, dude saying that there are exactly 99 wrong sentences is correct. durrrface

phoneutria
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### Re: Riddles

phoneutria wrote:first I thought, there are only two possibilities. a single sentence being correcy, or none, because they are all mutually exclusive.
but then, if none are correct, dude 100 would be correct. but if dude 100 is correct, then there would be 99 wrong sentences. so he can't be correct.
if 1 sentence is correct and 99 are wrong, dude saying that there are exactly 99 wrong sentences is correct. durrrface

You are still not exactly saying who is right and who is wrong and especially: why. So my questions again:
Do you mean that the sentence of the 99th person is correct? And if so: Why is the sentence of the 99th person correct? And what about the other persons? Please give a rationale why the sentence of the 99th person is correct and what about the other persons and why.

Arminius
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### Re: Riddles

Phoneutria you just got smacked on the hand with a ruler. You better tighten up kiddo.
Zoot Allures
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### Re: Riddles

Now I haven't looked at the problem but Im pretty fuckin sure Phoneutria would solve it faster than me.

So what kind of an asshole would have the nerve to walk right in here and insult a superior mathematician? This kind baby.
Zoot Allures
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### Re: Riddles

phoneutria wrote:first I thought, there are only two possibilities. a single sentence being correcy, or none, because they are all mutually exclusive.
but then, if none are correct, dude 100 would be correct. but if dude 100 is correct, then there would be 99 wrong sentences. so he can't be correct.
if 1 sentence is correct and 99 are wrong
, dude saying that there are exactly 99 wrong sentences is correct. durrrface

You are still not exactly saying who is right and who is wrong and especially: why.
Last edited by phoneutria on Thu Sep 24, 2015 12:08 am, edited 2 times in total.

phoneutria
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### Re: Riddles

lol I broke ILP

phoneutria
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### Re: Riddles

Hypothesis: arminius is a robot.

Oh, nevermind, he is German

this tab was purposefully left blank

[throws spitball at zoot]

phoneutria
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### Re: Riddles

Rest of answers here, armie. I had to break it down to fix the tabs.

So my questions again:
Do you mean that the sentence of the 99th person is correct?

so my answer again
yes

And if so: Why is the sentence of the 99th person correct?

Because all sentences say different things, therefore the only two possible answers is only 1 sentence is correct, and all sentences are wrong.
2 or more sentences being correct is impossible because they would negate one another.
all sentences wrong is impossible because that would make "there are exactly 100 wrong sentences" correct, so this option is paradoxical.
this only leaves one possibility, that only one sentence is correct. therefore 99 are wrong.
thus dude who said there are exactly 99 wrong sentences is correct.

And what about the other persons?

They're... wrong.

Please give a rationale why the sentence of the 99th person is correct and what about the other persons and why.

I basically just rephrased what i had already said, so I hope this is enough for your highness.

phoneutria
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### Re: Riddles

phoneutria wrote:
So my questions again:
Do you mean that the sentence of the 99th person is correct?

so my answer again
yes

And if so: Why is the sentence of the 99th person correct?

Because all sentences say different things, therefore the only two possible answers is only 1 sentence is correct, and all sentences are wrong.
2 or more sentences being correct is impossible because they would negate one another.
all sentences wrong is impossible because that would make "there are exactly 100 wrong sentences" correct, so this option is paradoxical.
this only leaves one possibility, that only one sentence is correct. therefore 99 are wrong.
thus dude who said there are exactly 99 wrong sentences is correct.

And what about the other persons?

They're... wrong.

Please give a rationale why the sentence of the 99th person is correct and what about the other persons and why.

I basically just rephrased what i had already said, so I hope this is enough for your highness.

Yes. and a bit .

That is right.

Arminius
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### Re: Riddles

phew goddamn

phoneutria
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