Cheryl's birthday: Difference between revisions
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(Find the birthday of Cheryl!) |
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Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. |
Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. |
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Cheryl gave them a list of 10 possible dates: |
Cheryl gave them a list of 10 possible dates: |
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May 15 May 16 May 19 |
May 15, May 16, May 19 |
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June 17 June 18 |
June 17, June 18 |
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July 14 July 16 |
July 14, July 16 |
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August 14 August 15 August 17 |
August 14, August 15, August 17 |
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Cheryl then tells Albert and Bernard separately the month and the day of the birthday respectively. |
Cheryl then tells Albert and Bernard separately the month and the day of the birthday respectively. |
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1) Albert: I don't know when Cheryl's birthday is, but I know that Bernard does not know too. |
1) Albert: I don't know when Cheryl's birthday is, but I know that Bernard does not know too. |
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2) Bernard: At first I don't know when Cheryl's birthday is, but I know now. |
2) Bernard: At first I don't know when Cheryl's birthday is, but I know now. |
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3) Albert: Then I also know when Cheryl's birthday is. |
3) Albert: Then I also know when Cheryl's birthday is. |
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So when is Cheryl's birthday? |
So when is Cheryl's birthday? |
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Revision as of 07:46, 22 October 2018
Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is.
Cheryl gave 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 the birthday respectively.
1) Albert: I don't know when Cheryl's birthday is, but I know that Bernard does not know too.
2) Bernard: At first I don't know when Cheryl's birthday is, but I know now.
3) Albert: Then I also know when Cheryl's birthday is.
So when is Cheryl's birthday?