[mseebach]

For outsiders, there are two elements to the puzzle: the encoding of the logic problem and the logic problem itself.

People might very well be able to solve even fairly complex logic problems without having been exposed to this tradition of encoding such problems.

The problem is stated as three persons having an odd, but casual conversation. To outsider that's all they're doing and to those the problem is impenetrable. Insiders, however, immediately recognise the informal protocol of logic quizzes that this is not a random casual conversation, it is carefully written to encode just enough information to be solvable as a logic problem. These insiders know to carefully extract (decode) this information. Only then do they solve the logic problem.

The "dishonesty" of the problem, which is confusing to people expecting the problem to be stated honestly, is that the conversation in the problem is entirely contrived, there is no way is would ever happened as part of a real world exchange about birthdays. This is fine for the intendeded reader, school kids trained in this protocol, but in "going viral" it went to a lot of unintended recipients.

[codeulike]

Yep, exactly.

[s_kilk]

This is exactly why I find these kinds of puzzles infuriating. It always hinges on some contrived, bullshit "trick" which has nothing to do with solving real problems.

[Nursie]

It's really not a trick. You simply take all the knowledge you are given and (this is important) don't make any additional assumptions or guesses or even really think of the participants as human, and.solve it like a math problem.

[TillE]

Yeah. I'm completely unable to do any of the stereotypical interview question puzzles which hinge on an "outside the box" trick, but I had no trouble recognizing this as a straightforward problem that you just work through.