A professor tells his class that he will give them a surprise examination sometime next week.

For our purposes, an examination is considered a "surprise" if on that day, the class is not 100% sure that they will get an examination. (If they only suspect it, the examination can still be a surprise.)

Having given the class this warning, is it still possible for the professor to give them a surprise examination next week? (Assume that he will not give them an exam if it will not be a surprise.)

I remember seeing this problem before and the solution was that the professor gives the exam IMMEDIATE after he tells them that he will give a surprise exam, since by the same logic as mentioned in The Solution, it cannot be on any of those days in the next week nor any other day BUT the current day.

Posted by Brainteaser on 2003-11-12 03:34:54