Do you still remember Xiaoming from the word problems?

Xiaoming is very busy…\--Reposted from D.\.\Do you still remember the first male protagonist "Xiaoming" in word problems from your childhood school years? Once there was a child named Xiaoming, who tirelessly appeared in various word problems and wandered through many Chinese essays, undoubtedly the biggest male protagonist in school textbooks. His various strange behaviors and out-of-this-world thinking often made teachers furious, turning their faces green, and also left his parents at a loss, laughing and crying at the same time… Xiaoming accompanied many children through unforgettable student years. It is not hard to see that Xiaoming's childhood was busy, complex, conflicted, and even filled with tragic tones…\First, the boring water pipe at Xiaoming's home\Problem: Xiaoming's home has a pond, with an inlet pipe and an outlet pipe. Opening only the inlet pipe can fill the empty pond in 30 minutes, while opening only the outlet pipe can empty the full pond in 20 minutes. If the inlet pipe is opened for a few minutes first and then the outlet pipe is opened, it takes 10 minutes to empty the pond. How many minutes was the inlet pipe opened first? (Recalling the word problems from our childhood, water-filling problems were the most convoluted, with one pipe filling water while another pipe drains it. Who in real life would open a pipe to let water drain out while filling a pond? Is such an application realistic? The sad part is that Xiaoming's home actually has such a pond, which suggests: his family either runs a bathhouse, or keeps fish, or the pipes are old and need to be replaced. The story really is boring, and there is also a concern of wasting water.)\Second, Xiaoming's hereditary forgetfulness\Problem: A. Classmates, this morning when going to school, Xiaoming was in such a hurry that after arriving at school, he realized he had forgotten his math textbook at home. Please help Xiaoming figure out a way. While his mother delivers it, Xiaoming also goes back and meets his mother on the way. Xiaoming's home is 750 meters from school, his mother walks 75 meters per minute, Xiaoming walks 50 meters per minute. If they simultaneously start from their respective locations towards each other, after how many minutes will they meet? B. Xiaoming's home is 2 kilometers from the train station. His father walked to the train station to go on a business trip to Beijing, but 15 minutes later, Xiaoming realized his father forgot his ID and hurriedly rode a bicycle to catch up. Knowing that his father walks 90 meters per minute and Xiaoming rides 240 meters per minute, how long will it take for Xiaoming to catch up to his father?(Like father, like son. Xiaoming has been forgetful since he was little, but you can't really blame anyone else — after all, he has a rather absent-minded father. His dad once forgot to bring his ID on a business trip, and Xiaoming forgot to bring his textbook to school. I really feel sorry for Xiaoming's mom, living with these two scatterbrains.)\3. Xiaoming's family doesn't have a private car, very unfortunate\Problem: Xiaoming goes from home to the gym to watch a game. On the way there, he walks for 5 minutes, then runs for 8 minutes to reach the gym. On the way back, he first walks for 10 minutes, then starts running, but ends up taking 3 minutes and 15 seconds longer than the trip there to get home. What is the ratio of his running speed to his walking speed? (If I had my classmate Xiaoming's sense of initiative back then, I might not be this fat now, even if he only exercised on a whim. Back then, I was too lazy to take a single step, and adults were the ones cycling to pick me up.)\4. Xiaoming always carefully calculates his pocket money\Problem: Xiaoming bought a fountain pen and spent 0.5 yuan more than half of the money he brought. Then he bought a ballpoint pen and spent 0.5 yuan less than half of the remaining money after buying the fountain pen. He also bought a notebook for 2.8 yuan, and finally had 0.8 yuan left. How much money did Xiaoming bring? (Correct answer: Xiaoming has senile dementia. He doesn't know how much money he brought and ended up getting beaten after arguing with the shopkeeper for too long.)\Xiaoming appears in various real-world math problems and gets into all sorts of trouble, leading netizens to gather all kinds of 'Xiaoming word problems' and label him as 'the most tragic protagonist of word problems.' A netizen named 'april' shared a relative speed problem with everyone: "It says Xiaoming goes from the end of a line to the front, then back again, can't remember what was asked, but every time I see this problem I feel sorry for Xiaoming." Xiaoming not only goes back and forth in line, but also on the highway: "There's a problem where Xiaoming is walking on the highway, constantly changing his speed, then encountering sudden incidents — in short, he walks back and forth for 4 hours, and finally the distance is asked." Many netizens felt sympathetic for Xiaoming: "Xiaoming, you can't walk on the highway, and yet you walked for 4 hours."Xiaoming not only has to run back and forth on the road, but also has to do some very painful physical labor: 'Xiaoming can make 180 pieces of clothing in 10 days. If he makes 20 more pieces per hour, how many hours will it take?' Response: 'It feels like Xiaoming should be an elementary school student, so why does he have to make clothes, and handcraft labor at that, not assembly line production... so exhausting.' And if Xiaoming wants to go shopping, things aren't much better: 'Xiaoming goes to the stationery store to buy 2B pencils. The shop owner said if he buys more, he gets a 20% discount. Xiaoming calculated that if he buys 50 pencils, it would be 6 yuan cheaper than buying at the original price. How much is each pencil?' Netizens said: 'Xiaoming has to use so much brain power just to buy something... as the main character of word problems, it's really not easy.'