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General Discussion Area / More 'thought of the day'...
« on: 28 August 2007, 21:22:35 »
(Found on the net, no copyright claimed)
The teacher tells her students that they should expect an exam some time during the next week. But she does not say when. The exam is to be unexpected.
But will it be unexpected?
Can the teacher give the exam on Friday? No, for if she gives it on Friday, then on Friday morning her students, knowing that they hadn't had the exam earlier in the week, will expect it.
What about Thursday? Well, as her students know that the exam cannot be on Friday, if she leaves it till Thursday, the exam will again be expected. So Thursday is out, too.
What about Wednesday? That, again, is ruled out. Her students know the exam cannot be on either Thursday or Friday, so if the teacher leaves it until Wednesday, the exam will again be expected.
But then Tuesday and Monday are also out, and for the same reason.
In short, the teacher cannot give an unexpected examination.
Yet, of course, she can. Can't she?
The teacher tells her students that they should expect an exam some time during the next week. But she does not say when. The exam is to be unexpected.
But will it be unexpected?
Can the teacher give the exam on Friday? No, for if she gives it on Friday, then on Friday morning her students, knowing that they hadn't had the exam earlier in the week, will expect it.
What about Thursday? Well, as her students know that the exam cannot be on Friday, if she leaves it till Thursday, the exam will again be expected. So Thursday is out, too.
What about Wednesday? That, again, is ruled out. Her students know the exam cannot be on either Thursday or Friday, so if the teacher leaves it until Wednesday, the exam will again be expected.
But then Tuesday and Monday are also out, and for the same reason.
In short, the teacher cannot give an unexpected examination.
Yet, of course, she can. Can't she?