Question: Peter tells Caspar and Tim: “My birthday is on one of the following days:”
- July 4,5 or 8
- August 6 or 7
- September 3 or 5
- October 3,4 or 6
Peter then tells Caspar the day of his birthday and Tim the month of his birthday. Then the following dialogue takes place:
- Caspar says: “I don’t know Peter’s birthday.”
- Tim responds: “I don’t know his birthday either, but I already knew you didn’t know.”
- Then Casper says: “Now I know his birthday!”
- And Tim adds: “Now I know it too!”
When is Peter’s birthday?