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Qetesuesi

C'mon Hpc Brains, Sort This One Out

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You can obviously rule out May 19 and June 18, since 18 + 19 appear only once.

The only way that any Bernard can know by himself the correct day is if it is one of the above. When Albert says "I know that Bernard does not know", this communicates the information that it cannot be in May or June..

Bernard now knows which day her birthday is on, we can rule out the 14th because that appears twice.

This leaves 3 possible dates, July 16th, August 15th & 17th.

Albert now knows what day her birthday is on.

If Albert was told her birthday was in August there would be two possible dates, therefore he would not know.

Therefore her birthday is on July 16th.

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July 16

Because the first guy knows that the day is not unique, that eliminates the possibility of May and June, which both have unique dates in them. When the second guy says that he now knows the birthdate, that eliminates the 14th, the day that is shared between the two remaining months. As the first guy now says that he knows the date, that means that it must be July 16 because July only has two possibilities and it's not the 14th.

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You can obviously rule out May 19 and June 18, since 18 + 19 appear only once.

The only way that any Bernard can know by himself the correct day is if it is one of the above. When Albert says "I know that Bernard does not know", this communicates the information that it cannot be in May or June..

Bernard now knows which day her birthday is on, we can rule out the 14th because that appears twice.

This leaves 3 possible dates, July 16th, August 15th & 17th.

Albert now knows what day her birthday is on.

If Albert was told her birthday was in August there would be two possible dates, therefore he would not know.

Therefore her birthday is on July 16th.

OK, fine, you beat me to it. :)

(I guess the explanation isn't necessary as it's spelled out at the end of the article.)

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OK, fine, you beat me to it. :)

(I guess the explanation isn't necessary as it's spelled out at the end of the article.)

It was in the Telegraph this afternoon. :)

TBH I didn't really understand it until I wrote it down.

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July 16th but I had to read a couple of explanations to understand it. The english is pretty poor.

That was why I didn't really understand the puzzle itself and declared it to be impossible to solve.

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July 16th but I had to read a couple of explanations to understand it. The english is pretty poor.

The English is appalling. Singapore is supposed to be one of the top-performing educational systems in the world, but that's what passes for English in schools?

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Dunno why the Chattering Classes make such a big deal of this. It sounds typical of the sort of problem that's been floating around for generations. The name of Martin Gardner springs to mind as one whose books of such things were popular when I was a lad.

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