Albert announces to his class that he plans to surprise them with a quiz sometime next week.
His students first wonder if the quiz could be on Friday of next next. They reason that it can’t: if Albert didn’t give the quiz before Friday, then by midnight Thursday, they would know the quiz had to be on Friday, and so the quiz wouldn’t be a surprise any more.
Next the students wonder whether Albert could give the surprise quiz Thursday. They observe that if the quiz wasn’t given before Thursday, it would have to be given on the Thursday, since they already know it can’t be given on Friday. But having figured that out, it wouldn’t be a surprise if the quiz was on Thursday either. Similarly, the students reason that the quiz can’t be on Wednesday, Tuesday, or Monday. Namely, it’s impossible for Albert to give a surprise quiz next week. All the students now relax, having concluded that Albert must have been bluffing.
And since no one expects the quiz, that’s why, when Albert gives it on Tuesday next week, it really is a surprise!
2026-04-11 20:11:38.1775938298
What do you think is wrong with following reasoning of 'students'?
747 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail At
1
The question is not if a quiz is a surprise, but when a quiz is a surprise. The students’ argument only demonstrates that one will always have foreknowledge of the quiz as some point beforehand, but up until the day before you don’t know.