Human race, but was chased by girls from all races

……

With the goal and direction, everyone immediately started thinking. Among them, Lin Tianlang frowned tightly. Although he had a headache, he also understood that the current challenge did require careful reasoning and calculation.

"The situation now is that we already know that every time the rod is pulled five times, the door will have a chance to be unlocked, and in this process, the length of the rod will also shorten. If we can't complete all the steps in the remaining six vibrations, then we may be trapped here." Shirley began to analyze following Xu Weiwei's thoughts.

"So we have to carefully calculate the position of each rotation to ensure that Door 2 is aligned with Room 8 at the critical moment." Qiuyue added, her voice carrying a hint of calm judgment.

"Not only that, we also need to figure out how to get back to the exit, right?" Long Xinyu scratched his head: "If we only get the key but can't get out, wouldn't that be a waste of effort?"

"Yes, this is crucial." Lin Tianlang rubbed his brows, and tried to think: "Just getting the key is useless. We also have to design a route so that after door No. 2 is unlocked, it can quickly align with the exit, so that we can leave smoothly."

"Besides, Weiwei, it seems that it is not possible." Long Xinyu looked at Xu Weiwei and said.

"What's the matter?" Originally Xu Weiwei was thinking with her eyes closed, as if she was deducing the pattern of the changing position of the door, but was suddenly interrupted by Long Xinyu.

"Now that Door 2 is at Room 4, no matter if you move it five times clockwise or five times counterclockwise, it can never be aligned with Room 8!"

There was some annoyance in Long Xinyu's voice. But it was obvious that the red-haired girl had made a mistake, so Xu Weiwei just smiled and explained: "We don't have to get it right the first time. We still have six chances. We can use three chances to align Door 2 with Room 8, and then use the remaining three chances to align Door 2 with the exit. In fact, there are still plenty of chances... In fact, we may not even need so many times."

Xu Weiwei's tone was a little excited. She gestured in the air with her fingers, and soon her brows relaxed.

"Math problems are your strong point, Xu Weiwei. I'm counting on you." Lin Tianlang said. Five seconds ago, he was still trying to think, but now he has given up. There is no other way. Asking a math idiot to think about mathematical logic is no different from asking him to die.

"Hey, can you be more motivated?" Xu Weiwei rolled her eyes at Lin Tianlang and said.

"Well... Actually, my math is not that good either..." Aniya said a little embarrassedly. In addition to Lin Tianlang and Aniya, Shirley and Long Xinyu, who were born in the magic world, were also unlikely to be good at math. In the magic world, math education is limited to teaching students addition, subtraction, multiplication and division. This is considered preschool education in the magic world, and it is impossible to dig deep into math like in the human world.

Qiuyue was also thinking with her eyes closed. She frowned slightly and sighed: "It's been... a long time since I thought about math-related puzzles."

Lin Tianlang and the others were all fourth-year students. Even though they had studied in the human world, they had not studied mathematics for four years. Not to mention that Qiuyue was one grade higher than everyone present. You know, even in the human world, for college students, if they did not need to study advanced mathematics, they would only need one year in their freshman year to forget all the mathematics they had learned in three years of high school. By the sophomore year, they would have forgotten everything they had learned in junior high school. After the junior year, they would only remember the basic four operations and simple equations they had learned in elementary school.

This is true for college students who have been in college for two years in the human world, and it is even more true for those who have been in the magical world for three or four years.

Fortunately, Xu Weiwei is here. As the girl's brows relaxed, her thoughts must have come to a conclusion.

"Alright, alright... you guys are such a fool. But it doesn't matter. I've already figured out what to do."

Xu Weiwei coughed lightly, then smiled triumphantly: "In fact, you may have over-complicated the problem. If you think about the whole mechanism directly, it is indeed difficult. But if you convert it into a complete mathematical problem, it is actually very, very simple, so simple that even an 8-year-old child can solve it."

As she spoke, Xu Weiwei began to analyze her ideas for the others: "Now, we have moved Door 2 to a position aligned with Door 4. Door 4 and Door 8 are facing each other. Whether they move clockwise or counterclockwise, the difference is exactly four positions."

"But each of our groups must move five times. We can't stop to open the door on the fourth time." Long Xinyu interrupted.

"Oh, I haven't finished yet, Xinyu, don't be anxious." Xu Weiwei said, "Yes, that's right. We must find a way to make Door 2 move only four steps clockwise or counterclockwise, so that it can be aligned with Room 8, and we can go in and get the key. This is actually very simple. If you think about it this way, you will find it."

"We know that each of our groups must move five steps. That means that every two groups will move a total of ten steps. We also know that moving left and right once is equivalent to not moving at all. So ten minus four is six, which is an even number. That is to say, our first six moves only need to be offset by left and right moves. In this way, after the moves are completed, we will still stay at the origin, Room 4, and then we can use the remaining four steps to move directly to Room 8."

After the analysis, Xu Weiwei raised her nose in delight: "So based on this deduction, in the total ten steps of the two groups, we only need to move seven steps clockwise and three steps counterclockwise, or vice versa. Then no matter what, the final result must be exactly aligned with Room 8!"

The reasoning was over, and Xu Weiwei snorted proudly, looking a little proud.

"Wow... Yeah, it seems to be true!" After listening to Xu Weiwei's derivation, Aniya suddenly understood. Qiuyue beside Aniya couldn't help but smile bitterly: "Ah... It sounds really simple... But it's been too long since I last touched a math problem, so it's really not easy to think of this level at once..."

"Ah? What? What? I, I don't seem to understand a little bit?" Seeing everyone showing an expression of "I understand", Long Xinyu was still confused, so he couldn't help but yelling.

"Don't ask me. You can watch what happens next." Lin Tianlang smiled. Following Xu Weiwei's instructions, Lin Tianlang first quickly pulled the right lever three times, causing the door to move three steps clockwise. Then, after the door had moved, he switched to the left lever and pulled it twice more.

I pulled the door twice on the left, plus three times on the right, which was exactly five times, enough for one set. After the last door was moved, the "earthquake" came as expected. This time, the vibration lasted a little longer, almost twice as long as the first time.

After the vibration passed, the two pull rods became shorter again.

Lin Tianlang did not hesitate. As soon as the room was settled, he quickly pulled the left lever five times. When the previous wave of operations was completed, the door of room 2 was aligned with room 5. Move five steps counterclockwise from the current position, and after the end, door 2 will be exactly aligned with room 8.

The second group of operations was over, and the familiar vibration came again, and the entire octagon began to shake. This time the vibration lasted longer, and at the same time the pull rod was obviously shortened again. Now the pull rod was only half as long as it was at the beginning.

The shaking stopped. Xu Weiwei took a deep breath, walked to Door No. 2, and reached out for the door handle.

"Creaky~~" The door was opened smoothly, and the interior of Room 8 was visible at a glance. There was nothing inside except the half - or 1/3 - of the key hanging in the air by a thin rope.

Xu Weiwei walked straight forward to the key floating in the center of the room. She reached out and took the key from the air, then turned around and smiled triumphantly at everyone.

"We succeeded!" Long Xinyu jumped up with joy.

"Great, I finally got it." Aniya breathed a sigh of relief and a smile appeared on her face.

"Don't be too happy, we still have to move the door to the exit position." Lin Tianlang reminded.

"I know this. Room 8 is only separated from the exit by Room 1. We just need to follow the logic just now and move the door two steps clockwise in ten moves. In other words, we need to move four steps counterclockwise first, and then six steps clockwise." Shirley said.

"Haha, that's a very typical example of learning by analogy, Xuexue! That's right, that's it!" Xu Weiwei walked out of Room 8, closed the door, and said to Shirley with a smile.

"Thanks for the compliment." Shirley smiled shyly. If Shirley hadn't been born in the magic world, she would have been an excellent math student in the human world.

Then the next step was easy. Just as Shirley said, first pull the left lever four times, then pull the right lever six times. During this time, everyone experienced two longer "earthquakes", and the lever was shortened to only one-fourth of its original length.

But it doesn't matter anymore, because Door 2 has returned to its original position - aligned with the exit.

"We've passed the customs successfully, let's go!" Lin Tianlang said happily. After opening the door, everyone held hands and walked out of the octagonal hall full of mechanisms and mysteries with the last part of the key.