At the last minute of the last class of the week, the logic teacher said to the class

Next week, if I can, I will hold a surprise quiz in one of our lessons.

The quiz will be about everything we've learned throughout the year, including homework. I'm going to make the hardest quiz I possibly can.

Those who will fail, will have to come to reinforcement lessons over the weekend.

Then the teacher exited the classroom, leaving everyone in slight shock. Some students went to Charlie, a very good student usually, who seemed surprisingly calm. When they came close, Charlie said

Don't worry, no one will have to study in the weekend.

How did Charlie know this?


  • Charlie didn't have any prior knowledge on the quiz, or on the teacher's whereabouts the following week.
  • This is the middle of the semester. There's a lot of material
  • There are 3 classes of logic a week

The teacher said

he will hold a surprise quiz if he can. But Charlie already knows about the "accident" the teacher will have this weekend.

| improve this answer | |
  • 1
    $\begingroup$ That's dark man $\endgroup$ – Dotan Dec 17 '17 at 16:18


The teacher said he would hold a surprise quiz if he can. But since he already told everyone about it, it's no longer a surprise, so he can't have a surprise quiz.

| improve this answer | |
  • $\begingroup$ But they dont know when it will be, that's the surprise $\endgroup$ – Dotan Dec 17 '17 at 16:50
  • $\begingroup$ @Dotan I mean, in my experience if the quiz is announced, it's not a surprise, even if the teacher doesn't specify a date $\endgroup$ – Quintec Dec 17 '17 at 16:55
  • $\begingroup$ For the sake of the question, not knowing the day counts as a surprise $\endgroup$ – Dotan Dec 17 '17 at 17:01

Not the answer you're looking for? Browse other questions tagged or ask your own question.