Three people draw lots before the exam and don't know how to sign them. After reading it, the person who untied the rope stretched out a finger. After asking several times, he said that this secret ca

Three people draw lots before the exam and don't know how to sign them. After reading it, the person who untied the rope stretched out a finger. After asking several times, he said that this secret can't be revealed. What is the secret? A finger can be interpreted in many ways: if three people are admitted, it means' all passed'; If you fail the exam, it is' all failed'; One in the exam is' one in the exam'; If you get two in the exam, it's' one failed'. No matter what the facts are, I can prove that my calculation is correct. "