Interview: The well is 7 meters deep. If you climb 3 meters during the day and fall 2 meters at night, how many days will it take to climb out?

In interviews with internationally renowned companies, intelligence test questions are often asked. In fact, this is not a mystery. The purpose of the interviewer is not to test the Mathematical Olympiad, but to see whether the applicant's brain reaction is fast or not. For Chinese people who have learned Mathematical Olympiad since childhood, it is a piece of cake, but for foreigners, some of them are really difficult.

A well-known multinational company once asked such a weird interview question, "You fell into the bottom of a 7-meter-deep well. The walls of the well are very slippery. You climbed up 3 meters during the day and slid down 2 meters at night. "How many days will it take you to climb out of the well?" The boss of a start-up company also imitated this question in campus recruitment. Some people say that this is just a math problem for primary school students, but for college students, the answers are also varied.

The first undergraduate student, probably taught by the physical education teacher, blurted out, "Add 3 meters during the day, lose 2 meters at night, and gain 1 meter a day. It will take seven days to climb out of the well and see the blue sky again." "The interviewer laughed secretly, and the boss also joked, "You can't starve to death if you crawl for seven days."

The second undergraduate student, probably a liberal arts student, was very down-to-earth. He took out his pen and started writing and drawing. "No, it won't take seven days, it should be six and a half days." The interviewer was very curious. , looking at him, he explained while drawing, "I crawled to the fifth day and fell back to the 5th meter at night. There were only 2 meters left from the wellhead. On the sixth day, I got up early and climbed to I climbed out at noon." The boss was stunned and applauded this young man for his stupidity.

The third undergraduate student, probably a philosophy student, thought dialectically for a few seconds and said, "This is not a math problem, this is an intellectual problem. I reached 4 meters on the fourth day. I climbed 3 meters in five days and climbed up to the wellhead with my hands. It took me five days to climb up." The interviewer laughed. The boss sighed: At least he is smarter than the second person. Nowadays, young people are playing games so stupidly that they finally found undergraduates with normal intelligence.

PS: In fact, weird interview questions often come from well-known large companies. For example, why are manhole covers round? For example, how many days does it take you to climb out of the well? This is a simple intelligence test, and it is really useful to see who has the fastest brain. Some innovative positions require not only creative vitality but also faster response than competitors. If you can understand the interviewer's intention and practice your thinking, you may be able to use it in the interview.