Denise's birthday brainteaser - Did you solve it? | Alex Bellos' puzzles

Alex Bellos set you a challenge: the sequel to Cheryl's birthday puzzle. Did you manage to solve it?
Watch Alex work it out and see if your answer matches. See you in two weeks for the next puzzle!

The Guardian on YouTube:

[bindair_dundat]

Lots of thinking. The fact that Albert, Bernard and Cheryl figured this out from a simple conversation without writing any of it down makes them geniuses. :D

[iamyou]

wait how does albert not have june or april because bernard doesn't have 11 or 12

[DaKoraqi]

he isn't allowed to get rid of all 3 if the April's, including the 13th and 15th of April. he can get ride of June 12 and June 17, because there are only 2 June's, and if it's not the 12th, and if Albert had June, he would know it's the 17th, therefore it's not June 12 or 17. but he misapplied that knowledge for April's. therefore April 13 and 15 should be on the board.

[johnathanpualilo]

i was so puzzeled juring this experience

[DaKoraqi]

he isn't allowed to get rid of all 3 if the April's, including the 13th and 15th of April. he can get ride of June 12 and June 17, because there are only 2 June's, and if it's not the 12th, and if Albert had June, he would know it's the 17th, therefore it's not June 12 or 17. but he misapplied that knowledge for April's. therefore April 13 and 15 should be on the board.

[DaKoraqi]

okay, he made a mistake, he can't get rid of the 3 April's. he can get rid of the 2 June's.

[tofvodka]

Why do you have to take out the entire 2004 if the statement is cheryl still doesn't know but she knows albert still doesn't know?

[grabern]

Better riddle:

Why would you call your child Denise?

[mariat.]

Happy birthday Denise!
I tried it on 14th May and I still failed.

[neonovaC]

I do think puzzle is not clear. He should have said albert can see bernards dates and that bernard can see cheryl dates and so on.. Otherwise its confusing when he says Albert know the date but he know bernard doesnt

[jonathanbr_]

Why didn't they just say what denise told them? They all want to know it, right? They would know in 3 single word sentences.

[viniciusavilaeichenberg]

That was awesome! it took me a lot of minutes to figure out the logic of the solution but it was worth it! Thanks for posting this. You got a new subscriber!

[itskelvinn]

Wait what? Albert said he knew, but yet there were still a ton of other options

[UV]

Can someone explain this puzzle clearly, it's so confusing!!!

[wNNNd]

Man the correct answer is 15 apr 2002 at first i thought it was 14 may 2002.