Three Logicians walk into a bar...

[etherial]

There's a logic puzzle that's been going around that has a bunch of my friends stumped. I don't know if it's really from a primary school assignment in Singapore (the syntax certainly reflects Singapore's mixed heritage), but I solved more complicated logic puzzles all the time in elementary school, so maybe

Comments

[leaper]

Why does the elimination of May 19 (via the elimination of 19) allow for the elimination of all the May options?

[etherial]

Albert eliminates the entire month of May (and June) in the first statement, which is roughly equivalent to "I know the month has no unique days".

[kestrel404]

The only reason I was having trouble with this is because I was treating Albert's first statement as logically ambiguous, because it is syntactically ambiguous. Because the statements are made in a separate format from the rest of the problem (the statements from Albert and Bernard are shown as a dialogue, and it is not stated to be AFTER Cheryl tells the two), then "but I know that Bernard does not know too", does not necessarily give any new data. Only when it is assumed that this statement gives some piece of new data to Bernard (hence his response, so it IS implied) can you solve this puzzle. Essentially, the wording & format is funky, probably because of the translation from Mandarin to English, so I was treating the statement as ambiguous

[kestrel404]

Aha. I just realized where the disconnect is

[siderea]

I encountered this a couple days ago. I mechanically figured out the first third (I drew a matrix) and then instantly knew the answer, and compulsively had to spend, like, a half an hour figuring out how I knew so I could be rigorous about it.

Way to go, intuition; maybe next time wait for your little brother, cognition?

ETA: I started doing logic puzzles pretty hardcore in elementary school. That's why my first instinct is to draw a matrix. Why doesn't everyone do this?