Li Hao has begun to close his eyes and think about this question, but Li Tai was stunned, a little confused, why did Lu Dongzan come up with such a question, this question seems to be too simple, three zhang during the day, two zhang at night, that day is one zhang, if you want to climb out of the well seven zhang deep, it naturally takes seven days, what's so difficult, why does Li Hao have to close his eyes and ponder, he can't figure it out.

The ministers can't figure it out, they all have similar ideas to Li Tai, the answer should be seven days, what's so difficult? Including Li Shimin, who was bored, drew a well on paper with a pen, and then drew a green worm......

After a long time, Li Shimin's eyes suddenly lit up, and he finally knew the difficulty of this question, he didn't expect that there was such a big trap in this question, he couldn't help but turn his head and look at Li Hao worriedly, I don't know if Li Hao can find this trap.

After about two minutes, Li Hao slowly opened his eyes, looked at Lu Dongzan, and said with an indifferent smile: "It will take five days and four nights." ”

When Lu Dongzan heard this, a trace of surprise flashed on his face, and he slowly clapped his hands and said: "Li Xianhou really deserves his reputation, admire!" Admire! ”

The ministers were stunned when they heard this, how could it be five days and four nights, it should be seven days and seven nights!

Li Tai also shouted excitedly: "Why is it five days and four nights? ”

Li Hao just wanted to speak, but he heard Li Shimin say: "Let me explain this question for you." ”

Lu Dongzan turned his head and looked at Li Shimin in surprise when he heard this, he didn't expect Emperor Tang to be able to guess this question, it seems that Emperor Tang is not simple.

Everyone focused on Li Shimin, Li Shimin was difficult to show a limelight, and said with a proud smile: "The green worm climbs three zhang during the day, and falls two zhang at night, one zhang for one day and one night, four days and four nights for four zhang, and on the fifth day, the green worm climbed up three zhang, plus the original four zhang, that is seven zhang, and it has reached the wellhead, so it is five days and four nights." ”

When everyone heard this, they suddenly realized, it turned out that there was such a big trap in this question, they were all deceived, and they all shouted "The emperor is wise", Li Shimin was so happy that he straightened his beard, and it felt really cool to be in the limelight!

At the center of the hall, Lu Dongzan spread his hands and said, "Li Xianhou, it's time for you to solve the problem." ”

Li Hao smiled and said, "Prime Minister Lu, don't blame me for not being kind, your questions are getting more and more difficult, in order to avoid long nights and dreams, I have to let you lose." ”

"Oh?" Lu Dongzan raised his eyebrows and smiled when he heard this, "It seems that Li Xianhou still has a big trick, Ge Dongzan is looking forward to it." ”

Li Hao sneered: "This is indeed a big move, I'm afraid it will be difficult for you to answer." ”

Li Tai on the side was an academic fan, and when he heard Li Hao say this, he couldn't hold it anymore and urged anxiously: "Li Hao, don't sell it, hurry up and ask the question!" ”

Lu Dongzan also said indifferently: "Li Xianhou, let's get the question." ”

Li Hao nodded and said, "Your Majesty, Weichen needs paper and pencils." ”

Li Shimin gave Xu Lian a look, Xu Lian handed Li Hao a pen and paper, Li Hao took the pen and paper, spread the paper in front of him, and then wrote the east, west, north and south on the four sides of the paper, according to the direction of the map, up and down, south, left, west, right and east. Then, Li Hao drew two parallel lines on the paper, east-west, and drew a few water waves in the middle of the parallel lines, and wrote the word "river", which represents a river.

At this point, Li Hao raised his head and asked Lu Dongzan: "Prime Minister Lu, can you understand what this is?" ”

Lu Dongzan smiled and nodded: "This is a river." ”

"It's good to understand." Li Hao smiled indifferently, continued to immerse himself in painting, drew a small circle at the bottom of the river ten centimeters, and marked - "Li family" next to the small circle, and then drew a small circle at the right twenty centimeters of the Li family, marked as - "Wang family", the Wang family is a little closer to the river, only six or seven centimeters.

Then Li Hao put down the pen and asked, "Prime Minister Lu, can you understand it now?" ”

Lu Dongzan nodded again: "These are two families, one surnamed Li and the other surnamed Wang." ”

"That's right." Li Hao picked up the painting, suddenly got up, and showed the painting to everyone, everyone looked at it for a while, I don't know why Li Hao wanted to make this picture, Li Shimin finally couldn't help it, and asked: "Poetry madness, is this your question?" ”

"Yes, Your Majesty." Li Hao turned his head to look at Lu Dongzan and asked, "Prime Minister Lu, now the Li family and the Wang family want to work together to fund the construction of two roads and a wharf, and the wharf will naturally be built by the river, as for the two roads, they must lead to the wharf from the Wang family and the Li family respectively, in order to save costs, the road is naturally built as short as possible, but it must meet the previous requirements, may I ask Lu Daxiang, where will the wharf be repaired, so that the total length of these two roads can be the shortest?" ”

Lu Dongzan was shocked when he heard this, and his eyebrows tightened to look at the painting in Li Hao's hand, he had to admit it...... He was stumped.

Lu Dongzan's eyes stared at the painting tightly, as if to see it through, and the ministers also saw the clues, Lu Dongzan is different from before, how is it different, when Lu Dongzan wanted to answer before, as long as he closed his eyes and pondered for a while, he could get the answer, which looked extremely relaxed, but this time it was different, Lu Dongzan's first time since the beginning of the battle of wits in front of the palace, showed such a dignified color.

Lu Dongzan frowned and stared at the painting for a long time, and suddenly said, "Can you lend me the pen and paper in your hand?" ”

Li Hao smiled generously and pushed a stack of paper and pen and ink in front of Lu Dongzan.

"Thank you." Lu Dong praised and thanked him, and drew a picture on the paper with a pen, which was almost exactly the same as what Li Hao had drawn, it was also a river and two small circles.

Next, Lu Dongzan tried to set up points by the river, and the point he set was the location where the wharf was built, and then from that point on the river, he started to connect with the "Li family" and the "Wang family".

However, Lu Dongzan tried for a long time, but still had no clue, on Li Shimin's desk, the sand in the hourglass was slowly leaking, time was passing little by little, Lu Dongzan had placed more than a dozen paper balls beside him, each picture was altered by him to the point of indistinction, and after destroying one, he quickly drew another one, and continued to try to find the correct location of the dock.

Li Hao looked at the busy Lu Dongzan, his expression was indifferent, he knew that this time Lu Dongzan lost, because the solution of this problem surpassed this era, and the use of geometric knowledge and physics knowledge, although the Pythagorean theorem was discovered a long time ago, but after that, geometry is often ignored, but some craftsmen use geometry and physics more, but the craftsmen have low knowledge, although they know how to use, but they don't know the reason, this is the authentic knowledge but do not know why, Therefore, it was difficult for these two disciplines to be carried forward in ancient times.

Li Hao knew that Lu Dongzan was proficient in arithmetic, but he guessed that geometry and physics should not be his forte, and now it seems that this is indeed the case.

After a long time, the last hourglass in the hourglass was gone, Li Shimin was overjoyed, and raised his voice: "It's time, you have lost!" ”

Lu Dongzan looked up in surprise and looked at the hourglass on the dragon case, sure enough, the sand had leaked, and he sat on the ground weakly, drooping his head, and remained silent for a long time.

Li Hao didn't feel pity for Lu Dongzan because of such a state, he smiled and bowed his hand to Lu Dongzan: "Prime Minister Lu, I have conceded." ”

Lu Dongzan looked up at him, staring at him deadly, his eyes were extremely complicated, he wanted to know the answer, but he didn't want to beg Li Hao, he was so conflicted in his heart.

This time, Li Tai didn't ask for an answer, Li Hao saw that Lu Dongzan was silent for a long time, raised his eyebrows and asked, "Don't you want to know the correct answer?" ”

Lu Dongzan snorted coldly: "If you lose, you lose, my skills are not as good as others, and I still need to know what the answer is, do you want to humiliate yourself!" ”

Li Hao raised his eyebrows and smiled evilly: "Aren't you afraid that there will be no answer to this question?" ”

Lu Dongzan was stunned for a moment when he heard this, and then sneered: "Then even if you are lucky, I can afford to lose!" ”