Coffee?

Posted by: CanukDenis

Coffee? - 07/08/13 10:57 AM

Four logicians in a restaurant have just finished lunch
when the waitress comes by and asks "Do all of you want coffee?"

The first logician answers "I don't know".

The 2nd and 3rd logicians also answer "I don't know".

The 4th logician answers "No"

Assuming all 4 responded with correct answers ,
how many want coffee and which ones , if any , want coffee.
Posted by: nell_nerhegeb

Re: Coffee? - 07/08/13 12:29 PM

.. I have a feeling I missed something laugh

The 4th doesn't want coffee.

The first three want coffee.
Posted by: BobH

Re: Coffee? - 07/08/13 01:02 PM

Nell, by my logic, you got it right. They take the waitress literally when she asks if they ALL want coffee. If the first one didn't want coffee, he would know that they then couldn't ALL want coffee so he would say no. It is only if he wanted coffee that he would have to answer, "I don't know" because he wouldn't yet know if every one of them wanted coffee.

The same goes for the second and third logicians until finally the fourth can say with certainty that they don't ALL want coffee because he doesn't.
Posted by: CanukDenis

Re: Coffee? - 07/08/13 01:12 PM

Ya'll got it!
The 4th logician could instead have said:
"bring 3 coffees"
Posted by: Redz

Re: Coffee? - 07/08/13 01:23 PM

birthday, BobH. Hope you have a great day grin

Joan wave
Posted by: Sherlock

Re: Coffee? - 07/08/13 01:35 PM

Happy Birthday, Bob! birthday
Posted by: BobH

Re: Coffee? - 07/08/13 01:43 PM

Thanks for the birthday wishes! penguin
Posted by: nell_nerhegeb

Re: Coffee? - 07/08/13 01:57 PM

Oh good, that was also my line of thought.

A Happy Birthday from me as well smile
Posted by: soot

Re: Coffee? - 07/08/13 08:59 PM

Welcome to the Garden Nell wave
Posted by: nell_nerhegeb

Re: Coffee? - 07/10/13 11:26 AM

Thank you soot smile I'm sure I'll come here again