The five surnames and seven Wangs had a bad start. They had been given a show of strength as soon as they came up. This was not a good sign and made them worry.
The second round of the competition was called the Bright Arithmetic Section. As the name suggested, it was similar to modern mathematics.
On the side of the Five Surnames and Seven Wangs was Lu Youjun, a branch of the Lu family of Fanyang, who was familiar with the Mathematics Department.
Lu Youjun wasn't the most outstanding person in the Lu Clan, but his strength in the Bright Arithmetic Department was definitely at the top of the Lu Clan.
Yesterday, when the family head suddenly summoned him, he thought that he had made a mistake. He did not expect that he would actually go to the Imperial Palace's Ming De Hall to compete with others in divination.
In his opinion, this was definitely a once-in-a-lifetime opportunity to show his face. If his performance was outstanding, perhaps His Majesty would be happy and reward him with an official position?
As the saying goes, if a worker wants to do a good job, he must first sharpen his tools. After being grateful to Lu Yanqing, Lu Youjun was so excited that he couldn't sleep. He took out all the books on Ming Arithmetic and read through all the difficult problems.
Although Wang Jingzhi had lost in the Jinshi examination just now, it did not affect Lu Youjun at all. After all, in his understanding, the rankings of the five surnames and seven surnames were the Cui family, the Lu family, the Li family, the Zheng family, and finally the Wang family.
The Lu family was closely behind the Cui family, and they even felt that they were stronger than the Cui family in private.
At this moment, the confident Lu Youjun still didn't put Qin Feng in his eyes. After all, the Department of Bright Arithmetic required talent. Even among the young disciples of the Lu family, those who knew how to do Bright Arithmetic were rare.
Lu Youjun looked at Qin Feng with contempt and said,"Now there are pheasants and rabbits in the same cage. There are thirty-five heads on top and ninety-four feet on the bottom. How many pheasants and rabbits are there?”
When Qin Feng heard this, wasn't this the same problem as the chicken and rabbit in the cage in the elementary school Mathematical Olympiad?
There were many ways to solve this kind of problem, such as setting up a set of equations with two variables.
Assuming that the number of chickens is X and the number of rabbits is Y, then two equations can be written:
X Y＝35；
2X 4Y＝94。
If X was 23 and Y was 12, there were 23 chickens and 12 rabbits.
"There are twenty-three pheasants and twelve rabbits," Qin Feng answered directly.”
The smile on Lu Youjun's face was still hanging on his face. At this moment, he suddenly froze, and his face was filled with disbelief.
Not all the officials present were good at arithmetic. They were also calculating in their hearts when they heard Lu Youjun's question.
However, before they could think of anything, Qin Feng had already said the answer. Could it be that he was just making things up?
But looking at Lu Youjun's expression of disbelief, Qin Feng's words were 80% correct.
They had encountered the problem of pheasants and rabbits in the same cage before, but this kind of problem really made them unable to start. They couldn't try it again and again, right?
However, why did Qin Feng say the answer without any hesitation? Furthermore, it was the correct answer?
Lu Youjun was unwilling to give up. He gritted his teeth and asked again,"Today, there is a chicken that is worth five yuan, a chicken that is worth three yuan, and a chicken that is worth five yuan. Three chicks are worth one. A hundred dollars for a hundred chickens. May I ask how many chickens, mothers, and chicks there are?"
This question was a 100-coin 100-chicken problem. It could still be answered with an equation, but it was equivalent to an indeterminate equation.
Assuming that the rooster, hen, and chick were x, y, and z respectively, the equation could be obtained according to the meaning of the question: 5x 3y 1/3z=100
In addition, if we set an integral k, we have: x=4k,y=25-7k,z=75 3k。
Because the chicken number x, y, and z could only be positive numbers, the k value that satisfied this set of equations could only be 1, 2, and 3.
By replacing k with 1, 2, and 3, it was easy to calculate that k was 1, then x was 4, y was 18, and z was 78.
There were also 4 roosters, 18 hens, and 78 chicks.
After Qin Feng said this answer, the officials were completely unsettled. This question was much more difficult than the pheasants and rabbits in the same cage. There was a rooster, a hen, and a chick. Just listening to it made one's head ache.
However, Qin Feng could still answer without hesitation. Could it be that Qin Feng is really a genius of the Bright Arithmetic Department?
Li Er wasn't good at calculating. He was a little confused after calculating in his heart, so he asked,"Lu You Jun, is Uncle Lan Tian's answer correct?”
Although Lu Youjun found it hard to believe, he did not dare to lie. He could only say,"Your Majesty, Uncle Lan Tian's answers are correct.”
Li Er had never seen Qin Feng's ability in the Department of Numerancy before, but he had to admire him now. He could answer such a difficult question casually.
This time, no one suspected Qin Feng of cheating. After all, although Lu Youjun was a branch of the Lu family, he was still a member of the Five Surnames and Seven Wangs. There was no motive for him to collude in advance.
"Qin Feng, tell me how you answered.”
Li Er was also interested in how Qin Feng solved these two questions so quickly. He could not help but ask.
The surrounding officials all pricked up their ears, ready to hear what Qin Feng had to say.
"Your Majesty, this kind of question is actually very simple. First, it's the problem of pheasants and rabbits in the same cage.”
Of course, Qin Feng couldn't say that he used the linear equations of two variables to get the answer. Otherwise, he would be treated as a lunatic.
Qin Feng thought of a "gentle" method and said,"If I whistle, the pheasant and the rabbit will both raise one leg. If I whistle again, the pheasant and the rabbit will raise another leg.”
Everyone was puzzled. Didn't they calculate how many pheasants and rabbits there were? Why did it turn into whistling and raising his leg? Could it be that he could tell how many there were just by raising his leg?
"We know that there are thirty-five pheasants and rabbits in total. After two whistles, they raised a total of seventy legs, so there are twenty-four legs left. May I ask who these twenty-four legs belong to?”
Lu Youjun was indeed worthy of being the one who had the best calculations among the people present. He immediately understood the key point and said excitedly,"Oh, I know, it's Rabbit's!”
Seeing Qin Feng nod his head, while the other officials were still confused, he also acted as the commentator and continued,
"These twenty-four legs belong to the rabbits. Because rabbits have four legs, two of them have already been raised, so these twenty-four legs belong to twelve rabbits.”
"So there are twelve rabbits in the cage, so there are twenty-three pheasants.”
After Lu Youjun said this, the officials finally understood.
It turned out that the problem of pheasants and rabbits being in the same cage, which had once frightened them, was actually so simple. It could be solved by whistling twice and raising his legs twice.
At the same time, many people started to admire Qin Feng. No matter what, he was able to make such a difficult question suitable for all ages. He indeed had some ability.
Li Er also understood. Qin Feng was able to make things easy. This kind of way of doing things and thinking gave him a refreshing feeling.
He thought to himself that he had indeed not misjudged Qin Feng. If he were to reform the imperial examinations, perhaps the Great Tang would truly shine with a different kind of vitality.
Lu Youjun had just been happy for a short while before he felt troubled again."But what about the second one? If one whistled, regardless of whether it was the father, mother, or chick, they all had two legs. No matter how they lifted it, it was all the same.”
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