Cheryl tells Albert the month and Bernard the day of her birthday from: May 15, May 16, May 19, June 17, June 18, July 14, July 16, August 14, August 15, August 17. Albert says 'I don't know, and I know Bernard doesn't know.' Bernard says 'I didn't know, but now I do.' Albert says 'Now I know too.' When is Cheryl's birthday?

Question

Accepted Answer

July 16. Albert eliminates May and June (which have unique days 18 and 19). Bernard can now deduce from his day. The only day that's unique within the remaining months (July, August) after excluding duplicates is 16, which only appears in July.

Cheryl's Birthday

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