So, let's assume that there are x ping-pong balls and badminton balls, and after taking them y times, the ping-pong balls will be gone.

So a series of equations are listed: ①x-5y=o (table tennis will disappear if you take y times); ②x-3y=6 (there are still 6 badminton players after taking y times. )

②-①，2y=6。

Therefore, y=3 ③.

Bring ③ into ① to get x= 15.

Answer: * * * I took it three times, and there were 15 table tennis and badminton in the box.

Also, the last thing I want to tell you is that this is my little skill in learning math application problems at that time. . . At that time, the math teacher always taught himself math several times a week, looking at the questions and solving the answers. This is an example in the book. Now that I think about it, it is still very useful, because only when you are familiar with the problem-solving ideas in the textbook can you solve other similar problems, otherwise, you will not be able to deal with those problems similar to the textbook knowledge, or you will still be in a hurry in the face of slightly changed questions. Therefore, it is still necessary to focus on the examples in the textbook and find out the general problem-solving ideas of such topics, which will be handy next time. Let's go O(∩_∩)O

I hope what I said will be useful to you.