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70 sats \ 1 reply \ @jakoyoh629 25 Apr \ on: Weekend Puzzle: Birthday Challenge math

June 17

Albert: I don't know the birthday, but I know that Bernard also doesn't know.

Force it to drop the 18th and 19th.

Bernard: At first I didn't know the birthday, but now I know.

It has to be June, because that's the only option left.

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30 sats \ 0 replies \ @SimpleStacker OP 26 Apr

The problem with your logic is that if the birthday was June 17, how would Albert be so confident that Bernard doesn't know the birthday?

Albert sees only June. From his perspective, it's possible that the birthday is June 18, in which case Bernard would know simply by seeing 18.

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