Chapter 1790 Victory in Mathematics

The old white-haired Daoist Zhenyang was overjoyed when he heard the words, and said, "That's great! Jushi Xia is really cheerful! There are several problems that have been bothering the poor Daoist all the time, and the first one is..."

Speaking of this, the old Taoist Zhenyang shook his head and said: "Today, there are pheasant rabbits in the same cage, with thirty-five heads on top and ninety-four feet on the bottom, how many are the pheasant rabbits?"

After Xia Ruofei listened to it, she suddenly showed a weird look, I can't tell! This old Taoist Zhenyang with thick eyebrows and big eyes is actually a math lover! No matter how polite his question is, it can't change the essence of a math problem! Isn't this the original chicken and rabbit cage problem?

The words of Zhenyang Laodao, translated into modern words, are: A chicken and a rabbit are locked in the same cage. There are thirty-five heads on the top and ninety-four feet on the bottom. How many chickens and rabbits are there? Only?

In ancient times, this may have been a very ingenious mathematical problem, but in this day and age, a junior high school student can easily solve it by writing a linear equation in two variables. Is this also called a problem?

After Master Zhenyang finished talking about this question, he said with a smile on his face, "Lady Xia, you can answer this question with a stick of incense."

As soon as he finished speaking, Xiaodaotong Qingfeng brought in a censer that had been prepared earlier, and a newly lit incense was inserted in the censer.

Xia Ruofei didn't know whether to laugh or cry, and said directly: "Daoist Zhenyang, don't be so troublesome, I have already 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 Ruofei smiled slightly and said, "There are 23 chickens and 12 rabbits, right?"

Naturally, the old Taoist Zhenyang couldn't really be trapped by a problem. The question he asked Xia Ruofei was actually a test.

Xia Ruofei believes that if other expedition members including Ling Qingxue also enter this scene, the old Taoist Zhenyang will also use exactly the same tone of voice to throw the question to them.

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

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

"Wait a minute!" said the old Taoist Zhenyang, "I want to know, what method did Jushi Xia use to solve the problem in such a short period of time?"

Xia Ruofei said in his heart: "A quadratic equation! Can't you just make it out of the mouth?"

However, the old Taoist Zhenyang must not understand binary linear equations. When Xia Ruofei was thinking about how to express the solution in an easy-to-understand way, he suddenly thought of an interesting problem-solving method that he saw on the Internet before. It seems absurd, but it can be calculated quickly.

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

The old Taoist Zhenyang nodded, but didn't say anything, because it was basically nonsense.

Xia Ruofei smiled and continued: "Let the chicken and the rabbit raise their two feet, then there should be seventy feet missing, right? There are still twenty-four feet left in the ninety-four feet, Because chickens only have two legs, after lifting them up, the remaining twenty-four feet on the ground are all rabbits. And each rabbit has raised two legs, so they all stand on two legs , twenty-four feet naturally correspond to twelve rabbits. There are thirty-five chickens and rabbits, twelve rabbits, and twenty-three chickens. Isn’t that the answer?”

Master Zhenyang was dumbfounded, he didn't expect the answer to be so simple.

After a while, he said with a strange expression: "How can the chicken and the rabbit raise their feet obediently? Also, the chicken raises both feet, what kind of posture is this..."

Xia Ruofei almost burst out laughing, he suppressed a smile and said: "Master Dao, this is not important, it's just a hypothesis! The point is that this method can get the answer the fastest,

isn't it? "

The old Taoist Zhenyang thought for a while, and said, "Jay Xia is talented! This method of solving the problem is very ingenious, and the poor Taoist admires it!"

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

"Of course!" said the old Taoist Zhenyang, "Poverty Daoist has another problem here, and Layman Wang Xia will not hesitate to enlighten me."

"Teacher please tell me!"

The old Taoist Zhenyang pondered for a moment, and then said: "There are things that I don't know how to count. When counting three or three, two are left, when five or five are counted, three are left, and when counting seven or seven, there are two left. How many things?"

have to! It is another classic ancient mathematics problem, and it also comes from "Sun Tzu's Mathematical Classics".

The translation of this question into modern words is: There is a pile of things, three and three numbers are finally left with two, five and five numbers are finally left with three, seven and seven numbers are finally left with two, find this pile of items quantity.

Xia Ruofei always had a faint smile on his face. There is a trap in this question. The 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 did not learn much mathematics faced this problem, they could get the answer one by one, but they probably ignored that there are many, many answers to this question. If only one is mentioned, it probably cannot be counted correct.

After the old Taoist Zhenyang asked the question, he looked at Xia Ruofei with a smile.

And Xia Ruofei also looked relaxed, and after a little thought, he said: "Master Dao, the answer to this question is not unique. There should be at least 23 items in this pile, followed by 128 items, and then there may be 233 items." One, and so on, adding 105 to each answer, you can get a new answer, so there are countless answers.”

Xia Ruofei's answer, expressed in mathematics, is 23+105n, where n is an integer greater than or equal to 1.

Xia Ruofei's answer is very rigorous, it can be said that it is watertight, even if the old Taoist Zhenyang wants to find a flaw, it is impossible to find it.

Therefore, he just pondered for a while, then nodded and said: "The layman is talented! This problem has been solved!"

This time, the old Taoist Zhenyang didn't even have the interest to ask Xia Ruofei to explain the calculation method, so he directly judged that Xia Ruofei solved the problem successfully.

Soon, the old Taoist Zhenyang went on to say: "There is one last question, I hope Jushi Xia can also answer the old Taoist question!"

Xia Ruofei secretly breathed a sigh of relief. He was afraid that the basic math problems would be endless. Although it was not difficult for him at all, it was a waste of time.

Moreover, the test on the first floor of the tower actually tested the mathematics skills, which was really unexpected.

Fortunately, the ability to set these levels is not too bad, there are only three questions arranged in total.

Therefore, Xia Ruofei has only one thought at this time, and that is to end it quickly!

Hearing the old Taoist Zhenyang's words, he hurriedly said: "Teacher please tell me!"

The old Taoist Zhenyang said seriously: "The last question is quite difficult, but I still can only give Layman Xia a little bit of work. I hope Layman Xia can continue to work hard and solve all the problems in one go!"

Xia Ruofei nodded with a smile, and said, "Please tell me, Taoist priest, and I will listen carefully!"

The old Taoist Zhenyang said: "There are twenty trees today, and four trees are planted in each row. Ask: How can I get sixteen rows of trees?"

Xia Ruofei was slightly taken aback when he heard the words, this time the old Taoist Zhenyang really came up with a worldwide mathematical problem! However, his sixteen-line map is not very challenging, because as early as the sixteenth century, mathematicians in ancient Greece, Rome, and ancient Egypt had already completed the sixteen-line map, and it was widely used in some Western countries. Decorative patterns of elegant buildings.

But Xia Ruofei thought about it, this secret realm has existed for at least thousands of years, and the sixteen-line atlas must not have been born at that time, so this question is very difficult. If Xia Ruofei didn't know the answer in advance, the time for a stick of incense must not be pushed Come out correctly drawn.

Fortunately, Xia Ruofei usually dabbles extensively, and has really seen this classic math problem.

Therefore, after Xia Ruofei listened to the question, she was also determined, knowing that she would definitely be able to pass this test.

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

The old Taoist Zhenyang thought that Xia Ruofei needed to deduce it, which is also normal. Many people used up paper to fill a room in order to solve this problem, but they may not be able to solve it.

Therefore, it is impossible for Xia Ruofei to deduce it directly in his mind, and he still needs to use paper and pen.

The old Taoist Zhenyang nodded with a smile, and motioned Tong Qingfeng to fetch the paper and pen, and specifically asked Qingfeng to grind the ink for Xia Ruofei.

Xia Ruofei came to the table, spread the paper on the table and pressed it with a paperweight, then he picked up the Langhao pen, dipped the ink in the inkstone, and started to draw on the paper.

A square quickly appeared on the paper, Xia Ruofei marked the four vertices black, and then accurately clicked two points on each side.

After Xia Ruofei entered the golden core stage, his physical fitness has also been comprehensively improved, and he has strong mental power, and he is very good at fine control. Therefore, he didn't need a ruler at all, but the squares he drew were quite accurate, and each line was straight, just like it was printed.

Then Xia Ruofei connected the two points on each side with the two points on the opposite side and the point on the next side clockwise away from them.

Another 24 straight lines were drawn exactly.

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

Xia Ruofei smiled slightly, and marked each vertex of the regular octagon formed by the intersection of the internal lines of the octagon in black.

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

The old Taoist Zhenyang thought that Xia Ruofei was making drafts and calculations, but he didn't expect that Xia Ruofei would start answering directly as soon as he came up, and he would finish it directly in such a short time. This is just a joke!

Xia Ruofei is given a stick of incense to think and answer each question, but every time Xia Ruofei comes up and solves the answer without thinking, let alone a stick of incense for one question, after answering the first three questions, the stick of incense will also Just burned a head off!

This is done?

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

Even those monks who are proficient in arithmetic usually fall into a long exam when faced with this problem, and those who can do it in a short time are rare.

However, Xia Ruofei completed the answer in just ten seconds, and wrote the answer without hesitation, as if it could be completed without thinking at all.

"Daoist Zhenyang, am I right to answer this way?" Xia Ruofei asked.

Master Zhenyang came back to his senses, with a wry smile on his face, he said, "Yes..."

Xia Ruofei said with a smile: "So, I can be of help to you..."

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

"Where is it! You are too famous!" Xia Ruofei said with a smile, "Actually, it is not difficult to arrange the sixteen lines. I can also arrange 18 or even twenty lines!"

"What?" Old Daoist Zhenyang's eyes widened when he heard that.