00:01
In this problem, it is said that three professors are seated in a restaurant, and the hostess asks them, does everyone want coffee? the first professor says, i do not know.
00:09
The second professor says, i do not know.
00:11
And the third professor says, no, not everyone wants coffee.
00:14
Now, we want to determine how the hostess figures out who wanted coffee.
00:19
So we have a total of three professors, one, two, and three.
00:24
Now, note that the first professor says, i do not know, no, meaning that the 1st professor does not know whether everyone wants coffee.
00:31
Now, if the 1st professor did not want coffee, then the 1st professor would have known that not everyone wants coffee...