Surprise examination
The teacher announces "there will be an examination next week, but you will never find out beforehand on which day it would be." A smart student then starts reasoning about it: The examination should not be on Friday because on Thursday I will definitely know it, but again if it is not on Friday then it should not be on Thursday either for the similar reason. By such induction, it can’t happen at all ! The teacher must have told a lie! " However, next Monday they indeed have a surprise exam. It turns out that the teacher did not lie.
- 开放问题 | Time: 4:14 pm (UTC+8)

You’re tired le, man~~
Comment by King of Kruislaan & Molukken — June 20, 2007 @ 11:42 am