The old white-haired Taoist Zhenyang showed joy when he heard this and said, "It's great! Mr. Xia is indeed a cheerful person! There are several problems that have always troubled me, and the first problem is..."

Speaking of this, the old Taoist Zhenyang shook his head and said, "Now there are pheasants and rabbits in the same cage, with thirty-five heads on top and ninety-four feet on bottom. What are the pheasants and rabbits on top?"

After hearing this, Xia Rufei suddenly showed a strange look, and he couldn't tell it! This old Taoist Zhenyang with thick eyebrows and big eyes was actually a math enthusiast! Even if his problem was so literary, it could not change the essence of this math problem! Isn't this the original chicken and rabbit cage problem?

The words of the old Taoist Zhenyang are translated into modern words: There are chickens and rabbits locked in the same cage, with thirty-five heads on the top and ninety-four legs on the bottom. How many chickens and rabbits are there?

In ancient times, this might have been a very clever mathematical problem, but in this era, a junior high school student can easily solve it. Just make a binary equation of first order. This is also called a difficult problem?

After the old Taoist Zhenyang finished speaking this question, he smiled on his face and said, "Mr. Xia, you can have a stick of incense to answer this question."

As soon as he finished speaking, the Taoist Tong Qingfeng brought in an incense burner that had been prepared, and a newly lit incense was inserted into the incense burner.

Xia Ruofei was amused and cried, and said directly: "Master Zhenyang, there is no need to be such a trouble. I have solved this problem."

The old Taoist Zhenyang raised his eyebrows and said, "The layman is so fast? Then tell me, what is the answer?"

Xia Rufei smiled slightly and said, "23 chickens and 12 rabbits, right?"

It is naturally impossible for the old Taoist Zhenyang to be really trapped by the difficulties. The questions he asked Xia Rufei were actually a test.

Xia Rufei believed that if other expedition members, including Ling Qingxue, would also enter this scene, the old Taoist Zhenyang would also throw the problem to them in the same tone.

As soon as Xia Ruofei said the answer, the old Taoist Zhenyang couldn't help but raise his eyebrows and said, "This is indeed the answer to this question..."

"So, I have solved this problem?" Xia Ruofei asked with a smile.

"Let's go!" said the old Taoist Zhenyang, "I want to know what method did Mr. Xia use to calculate to solve it in such a short time?"

Xia Ruofei said in his heart: "Binary equations are! Isn't it done by just verbally calculating?"

However, the old Taoist Zhenyang must not understand the binary equation. When Xia Rufei was considering how to express the solution in a simple and easy-to-understand way, he suddenly thought of an interesting problem-solving method he saw on the Internet before. Although it seemed a bit ridiculous, it was indeed able to calculate it quickly.

So, Xia Ruofei smiled and said, "My method is very simple! Taoist priest, there are thirty-five heads, which means there are thirty-five chickens and rabbits in total, right?"

The old Taoist Zhenyang nodded and did not say anything, because this was basically nonsense.

Xia Ruofei smiled and continued, "If the chicken and the rabbit lift both their feet, they should have lost seventy feet, right? There are twenty-four feet left on the ninety-four feet, because the chicken only has two feet. After they are lifted, the remaining twenty-four feet on the ground are all rabbits. And each rabbit lifts two feet, so they stand on both feet, and the twenty-four feet naturally correspond to twelve rabbits. There are thirty-five chickens and rabbits in total, and twelve rabbits, so the chickens are naturally twenty-three. Isn't the answer here?"

The old Taoist Zhenyang was stunned. He didn't expect that the answer would be so simple.

After a while, he said with a strange look on his face: "How can the chicken and the rabbit lift their feet obediently? Also, the chicken lifts both feet, what is the posture..."

Xia Ruofei almost burst out laughing. He laughed and said, "Master, this is not important, it's just a hypothesis! The point is that this method can get the answer as quickly as possible, right?"

The old Taoist Zhenyang thought for a while and said, "Mr. Xia is a talented person! This method of solving problems is very ingenious, I admire it!"

"So, is this problem solved?" Xia Ruofei asked with a smile.

"Of course!" said the old Taoist Zhenyang, "I have another problem here. I hope Mr. Xia will give me advice."

"Please say it, Taoist priest!"

The old Taoist Zhenyang pondered for a moment, then spoke, "There are things that don't know the number, there are two left in three numbers, two left in five numbers, and two left in seven numbers. Ask about the number of things?"

I'm sure! Another classic ancient mathematics problem, and it also comes from.

This question is translated into modern words: There is a bunch of things, three numbers are left in the end, five numbers are left in the end, and seven numbers are left in the end, two in the end, and find the number of these piles of items.

Xia Rufei always had a faint smile on his face. There is a trap for this question. This trap is: the answer to this question is not unique. To be precise, it should be an arithmetic sequence with a difference of 3*5*7. If the ancients who have not learned much mathematics faced this question, they could get answers by number test, but they are likely to ignore that there are many, many answers to this question. If they only say one, it is probably not correct.

After asking the question, the old Taoist Zhenyang looked at Xia Rufei with a smile.

Xia Rufei also looked relaxed and said after thinking for a moment: "Master Taoist, the answer to this question is not the only one. There should be at least 23 items, followed by 128, and then there may be 233, and so on. Adding 105 to each answer can get a new answer, so there are countless answers."

Xia Rufei's answer is expressed in mathematical calculation, that is, n is an integer greater than or equal to 1.

Xia Rufei's answer was very rigorous, and it can be said that it was completely invisible. Even if the old Taoist Zhenyang wanted to find flaws, it would be impossible to find them.

So, he just pondered for a moment and nodded and said, "A master and talented man! This question has been solved!"

This time, the old Taoist Zhenyang was no longer interested in asking Xia Rufei to tell him about the calculation method, and directly determined that Xia Rufei had successfully solved the problem.

Soon, the old Taoist Zhenyang continued: "There is another last question. I hope Mr. Xia can also solve the old Taoist's doubts!"

Xia Rufei secretly breathed a sigh of relief. He was afraid that these basic math problems would never end. Although it was not difficult for him, it was a bit too wasteful of time.

Moreover, the test on the first floor of this tower actually tests math skills is really unexpected.

Fortunately, the powerful people who set these levels are not too bad, so they only arranged three questions in total.

So, Xia Rufei had only one idea at this time, and that was to end it quickly!

He heard the words of the old Taoist Zhenyang and hurriedly said, "Please say it, Taoist priest!"

Zhenyang said seriously: "The last question is quite difficult, but I can only give Mr. Xia a stick of incense. I hope Mr. Xia can continue to work hard and solve all the problems in one go!" Weichang

Xia Ruofei nodded with a smile and said, "Psychologist, please speak, listen carefully!"

The old Taoist Zhenyang said, "There are twenty trees now, and four trees are planted in each row. Question: How can you get sixteen trees?"

Xia Rufei was slightly stunned when he heard this. This time, the old Taoist Zhenyang really came up with a global mathematical problem! However, his sixteen-row row was not very challenging, because mathematicians from ancient Greece, Rome, and Egypt had completed the sixteen-row chart, and were widely used in the decorative patterns of some elegant Western buildings.

However, Xia Rufei thought about it again that this secret realm has existed for at least a few thousand years, and the Sixteen-line map must have not been born at that time, so this question is very difficult. If Xia Rufei had not known the answer in advance, the correct drawing method would definitely not be able to be drawn in one stick of incense.

Fortunately, Xia Rufei is widely experiencing and has really seen this classic math problem.

Therefore, after hearing the question, Xia Rufei felt very calm and knew that he would definitely pass this level.

He smiled and said, "Master Zhenyang, can you give me paper and pen?"

The old Taoist Zhenyang thought Xia Rufei needed to deduce it, which is normal. Many people can fill a room with paper to understand this problem, but it may not be able to solve it.

Therefore, Xia Rufei could not deduce it directly in his mind, and he still had to use paper and pen.

The old Taoist Zhenyang smiled and nodded, signaling the Taoist boy Qingfeng to get the paper and pen, and specially instructed Qingfeng to grind the ink for Xia Rufei.

Xia Rufei came to the table, spread the paper flat on the table and pressed it with paperweight. Then he picked up the wolf brush, dipped it in the inkstone, and started to draw on the paper directly.

A square soon appeared on the paper. Xia Rufei marked the four black marks, and then accurately pointed two points on each edge.

After Xia Rufei entered the Golden Elixir Stage, his physical fitness was also comprehensively improved. He had strong mental power and was very outstanding in fine control. Therefore, he did not need a ruler at all. The squares he drew were quite accurate, and each line was straight, just like it was printed.

Then Xia Rufei connected the two points on each side to the two points on the opposite side and the point away from them clockwise.

There were 24 straight lines, and they were drawn without any mistakes.

In this way, an octagon has been formed inside the square.

Xia Rufei smiled slightly and marked each regular octagon formed by the intersecting internal lines of the octagon to blacken.

Before the old Taoist Zhenyang could react, Xia Rufei leaned his brush on the inkstone and said with a smile: "Master Zhenyang, I have finished it!"

The old Taoist Zhenyang thought Xia Rufei was drafting and calculating, but he didn't expect that Xia Rufei would start answering directly as soon as he came up, and it was completed directly in such a short time. This is simply a joke!

Each question gives Xia Rufei a stick of incense to think and answer, but Xia Rufei always comes up and solves the answer without thinking. Not to mention one question and one stick of incense, after answering the first part of the three questions, the incense stick has just burned one head!

Is this done?

The old Taoist Zhenyang was a little unbelievable, but he looked at the map drawn by Xia Rufei and immediately knew that Xia Rufei had already answered this question.

Even those monks who are proficient in mathology usually fall into long exams when facing this problem. There are very few people who can do it in one stick of incense.

However, Xia Rufei finished the answer in just a dozen seconds, and wrote the answer without hesitation, as if it could be completed without thinking.

"Master Zhenyang, is my answer right?" Xia Ruofei asked.

The old Taoist Zhenyang came to his senses, with a wry smile on his face, and said, "Yes..."

Xia Ruofei smiled and said, "So, I'm just helping you..."

"Of course!" said the old Taoist Zhenyang, "Mr. Xia is indeed extremely intelligent, I admire him!"

"Where are you! You're too proud!" Xia Ruofei said with a smile, "Actually, the arrangement of these sixteen lines is not very difficult. I can still draw 18 or even twenty lines of maps!"

"What?" The old Taoist Zhenyang suddenly widened his eyes when he heard this, "Mr. Xia, do you think this is true?"

Xia Ruofei nodded with a smile and said, "Of course it's true! However, in the Taoist priest's question, he only requires drawing 16 lines of arrangement, so I answered as required."

"Yes, yes! I have not refused to admit the answer from Mr. Xia." Zhenyang said quickly, "But if Mr. Xia doesn't mind, can you draw the Eighteen-line map and the Twenty-line map you mentioned?"

Speaking of this, the old Taoist Zhenyang quickly added: "This can also be included in the answer to the last question. If the answer is better, then the thank you gift from our Zhenyang Temple to the lay Buddhist will be even richer! Mr. Xia, how about it? Draw another stroke?"

This is equivalent to adding points if you answer the additional questions correctly, and no points will be deducted if you answer the wrong questions.

As Xia Rufei, who has experienced nine years of compulsory education, has long been familiar with this model, so he is not surprised.

However, when she was a student, Xia Rufei was always too lazy to study additional questions.

And today, when he heard that he would draw more lines of maps, the gift would be richer, and his eyes suddenly lit up.

Obviously, that is to say, the higher the quality of answering questions, the greater the reward for the task given in the end!

How could Xia Rufei refuse such a home-delivered benefit?

What's more, this may be a difficult problem for other monks, but for Xia Rufei, it is a totally a bonus question!

Because of the problem of this twenty trees, in the 18th century, the mathematician Gauss had already guessed that he could rank eighteen rows, but until his death, he did not come up with a formal map. Until the 19th century, the American interesting mathematician Lloyd completed Gauss' conjecture and drew eighteen rows of maps. By the end of the 20th century, electronic computer technology flourished, and two masters successfully completed the 20-row array map with the help of computers.

Xia Rufei has seen and kept these two maps in his heart.
Chapter completed!