Card 5 of 82
The Top Students' Class
A man inspecting a school notices that every time a teacher asks a question, many students are ready to answer. Each time the teacher picks a different student, and the answer is always correct.
Solution: The teacher told the students to raise a hand for every question. If they knew the answer, they had to raise their right hand; otherwise, their left. That way the teacher could always pick from among the students who knew the answer.