Puzzle #99: World’s Most Famous Puzzle Currently!

I am simply amazed how one single puzzle has proliferated across the social media in the last 10 days – the puzzle from Singapore, popularized by Alex Bellos’ blog in The Guardian. Many of you would have seen this, but I thought it is a nice puzzle, and hence putting it on the blog. This will be an interesting one to go through even with younger children.

Here is the puzzle:

Albert and Bernard Just became friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates:

May 15            May 16               May 19

June 17           June 18

July 14            July 16

August 14       August 15          August 17

Cheryl then tells Albert and Bernard separately the month and the day of her birthday respectively.

Albert: I don’t know when Cheryl’s birthday is, but I know that Bernard does not know too.

Bernard: At first I did not know when Cheryl’s birthday was, but now I know

Albert: Then I also know Cheryl’s birthday.

So when is Cheryl’s birthday?

As always, please send your answers directly to me at alokgoyal_2001@yahoo.com. If you like the puzzle, please share it with others. If you have interesting puzzles to share, please send them to me at my e-mail given above.

Happy birthday!

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5 Responses to Puzzle #99: World’s Most Famous Puzzle Currently!

  1. Deepa Salem says:

    Many of your puzzles are more difficult than this.. kind of surprised that this one is so written about 🙂

  2. Saurabh Aggarwal says:

    I think its 15th aug.

    Regards, Saurabh aggarwal

    Sent from my iPhone


  3. P R KUMAR says:

    As 18 and 19 are unique so they r cut out.. .with may and June months together Left days July and Aug… So if Bernard exactly knows date as he says “now I know d day” is July only as otherwise he would b confused between 15 and 16 Aug but he was not confused so its July 16

  4. anonymous says:

    July 16th

    First comment eliminates May and June
    Second comment eliminates the 14th
    Third comment eliminates August

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