About the tortoise's brain teaser, the answer is that the tortoise is listening to the story and forgets the question.

I don't know a joke about this question. I don't know if it is the one you said. Once upon a time, there was a prime minister who wanted to kill a turtle, and the turtle begged. Then the Prime Minister said that if you reach 10,000 Jin, I won't kill you. If you weigh 9999 Jin, the Prime Minister will kill him, so he goes back to get the tools. At this time, a seahorse gave the turtle an idea and waited for the prime minister to come back and weigh himself. When the Prime Minister heard this, he said that it was exactly 10,000 Jin and asked how it was. ! !