Xiao Pu (now working in minimally invasive surgery, I encountered this question last year): This question is still simple compared with some other minimally invasive questions, but it still makes my head big. That's how I did the problem at that time. If it is broken twice, it should be divided into three parts. I divided the gold bar into three parts: 1/7, 2/7 and 4/7. In this way, I can give him 1/7 on the first day; On the second day, I gave him 2/7 to get my 1/7 back. On the third day, I will give him another 1/7, plus the original 2/7 is 3/7; On the fourth day, I gave him the 4/7 piece and asked him to find the two 1/7 and 2/7 gold bars. On the fifth day, give him another 1/7; The sixth day is the same as the second day; The 1/7 that was found for him on the seventh day.
Example 2: Now Xiaoming's family has crossed a bridge. It is dark when crossing the bridge, so there must be a light. Now it takes 1 second for Xiaoming to cross the bridge, 3 seconds for Xiaoming's brother, 6 seconds for Xiaoming's father, 8 seconds for Xiaoming's mother and 12 seconds for Xiaoming's grandfather. At most two people can cross this bridge at a time, and the speed of crossing the bridge depends on the slowest one, and the light will go out 3 seconds after it is lit. Ask Xiaoming's family how to cross the bridge.
Reference answer: This kind of intelligence question actually examines the ability of the candidate to solve problems under limited conditions. Specific to this topic, many people often think that Xiao Ming should come and go with a light, which saves the most time, but in the end, no solution can be found. But to change our thinking, we can decide who will come and go with the light according to the specific situation, as long as we make some changes slightly: the first step, Xiaoming crosses the bridge with his brother, and Xiaoming comes back, which takes 4 seconds; In the second step, Xiaoming crossed the river with his father and his younger brother came back, which took 9 seconds. The third step, mom and grandpa crossed the river, and Xiaoming came back, which took 13 seconds; Finally, Xiaoming and his younger brother crossed the river, which took 4 seconds, and the total time was 3 seconds. How thrilling!
Expert's opinion: This kind of topic mostly appears in the recruitment interview of multinational enterprises, which plays an extremely obvious role in examining a person's thinking mode and the ability to change thinking mode. According to some studies, this ability is often closely related to the state of strain and innovation in work. Therefore, when answering these questions, we must break through the mindset, try to consider the problem from different angles, constantly think in reverse and empathy, and connect the questions with the familiar scenes to avoid confusion.
Now, let's start to test everyone:
Puzzle: Card guessing
Introduction: This is a classic interesting logic problem.
Details:
Mr. S, Mr. P and Mr. Q know that there are 16 playing cards in the drawer of the table: A, Q and 4 of hearts, J of spades, 8, 4, 2, 7, 3 of flowers, K, Q, 5, 4 and 6 of diamonds, A and 5. Professor John picked out a card from these 16 cards and told Mr. P the number of points in this card and Mr. Q the color of this card. At this time, Professor John asked Mr. P and Mr. Q: Can you infer what this card is from the known points or colors? So, Mr. S heard the following conversation: Mr. P: I don't know this card.
Mr q: I know you don't know this card.
Mr. P: Now I know this card.
Mr. q: I know, too.
After listening to the above conversation, Mr. S thinks about it and then correctly deduces what this card is.
excuse me: what is this card?
A collection of classic puzzles
Introduction: See how much you know?
details:
1. A manager has three daughters, and the ages of the three daughters add up to 13, which is equal to the manager's own age. A subordinate already knows the manager's age, but still can't determine the age of the manager's three daughters. At this time, the manager said that only one daughter's hair is black, and then the subordinate knew the age of the manager's three daughters. What are the ages of the three daughters? Why?
2. Three people went to a hotel and stayed in three rooms. Each room cost $1 yuan, so they paid the boss $3. The next day, the boss thought that only $25 yuan was enough for the three rooms, so he asked my younger brother to return $5 to the three guests. Unexpectedly, my younger brother was greedy and only returned $1, so he secretly took $2, which was equivalent to the three. But at the beginning, the three of them paid $3, so there was still $1?
3. There are two blind people. They both bought two pairs of black socks and two pairs of white socks. Eight pairs of socks are made of the same cloth and the same size, and each pair of socks is connected by a trademark paper. Two blind people accidentally mixed up eight pairs of socks. How can each of them get back two pairs of black socks and two pairs of white socks?
4. One train leaves Los Angeles for new york at a speed of 15 kilometers per hour, and another train leaves new york for Los Angeles at a speed of 2 kilometers per hour. If a bird starts with two trains at a speed of 3 kilometers per hour, starts from Los Angeles, meets another train and returns, and flies back and forth in turn until the two trains meet, how long does the bird fly?
5. You have two jars, 5 red marbles and 5 blue marbles. Choose one jar at random, and put one marbles into the jar at random. How can you give the red marbles the best chance to be selected? What is the exact probability of getting the red ball in your plan?
classic interview questions: interesting puzzles for foreign companies
6. You have four jars containing pills, each of which has a certain weight, and the contaminated pills are the uncontaminated weight+1. Weigh only once, how can you tell which jar is contaminated?
7. For a batch of lamps numbered from 1 to 1, all the switches are turned up (on), do the following: dial the switch in the opposite direction for every multiple of 1; A multiple of 2 dials the switch again in the opposite direction; A multiple of 3 turns the switch again in the opposite direction ... Q: Finally, the number of the light in the off state.
8. Imagine you are in front of a mirror. Excuse me, why can the image in the mirror be upside down, but not upside down?
9. A group of people have a party, each wearing a hat. There are only two kinds of hats in black and white, and there is at least one black one. Everyone can see the color of other people's hats, but not their own. The host first shows everyone what hats others are wearing, and then turns off the lights. If someone thinks they are wearing a black hat, they will slap themselves in the face. The first time I turned off the lights, there was no sound. So I turned on the light again, and everyone watched it again. When I turned off the light, it was still silent. It was not until the lights were turned off for the third time that there was a slap in the face. How many people are wearing black hats?
1. Two rings with radii of 1 and 2, respectively. The small circle goes around the big circle once inside the big circle. How many times did the small circle turn itself? If outside the big circle, how many times does the small circle turn by itself?
11. 1 yuan pays for a bottle of soda, and after drinking it, two empty bottles are exchanged for one bottle of soda. Q: You have 2 yuan money, how many bottles of soda can you drink at most?
How to determine the hat color
Introduction: This is a classic interesting logic problem.
Description:
There are 3 red hats, 4 black hats and 5 white hats. Let 1 people stand in a line from short to high and put a hat on each of them. Everyone can't see the color of his hat, but he can only see the colors of the hats of those standing in front. (So the last person can see the color of the hats on the heads of the nine people in front, while the first person can't see anyone's hats. Now, from the last person, ask him if he knows the color of the hat he is wearing. If he says no, he will continue to ask the person who booked the boat before him. Suppose that the person at the front must know that he is wearing a black hat. Why?
Call Apple Problem
Introduction: It's not a brain trick, let's think about it.
Description:
There are 1 boxes with 1 apples in each box, of which one box has 9 apples, and the others are 1 catty. It is required to use a scale, only once, to find out the box containing 9 pairs/pieces.
The problem of prisoners' survival
Introduction: A puzzle that really stumbles hundreds of millions of people is an interview question of Microsoft.
Details:
Five prisoners catch mung beans in sacks containing 1 mung beans on the 1st-5th respectively. It is stipulated that each prisoner should catch at least one mung bean, and those who catch the most and the least will be executed. Moreover, they can't communicate with each other, but when catching, they can find out the remaining number of mung beans. Ask which of them has the best chance of survival? Tip:
1. They are all very smart people.
2. Their principle is to save their lives first, and then kill more people.
3,1 pieces don't have to be divided up.
4. If there is any duplication, it will be considered as the largest or smallest, and they will be executed together.
Table tennis problem
Introduction: This question was modified by the website of Chinese ballads.
Detailed introduction:
Suppose there are 1 ping-pong balls arranged, and two people take turns to put the ball into their pockets. The winner is the one who can get the 1th ping-pong ball. The condition is: the person who takes the ball must take at least one at a time, but not more than five at most. Q: If you are the first person to take the ball, how many should you take? How can I take it in the future to ensure that you can get the 1th table tennis?
goat's speed
Introduction: None
Detailed introduction:
Professor Lum said, "Once I witnessed a duel between two goats, which led to an interesting mathematical problem. One of my neighbors has a goat, which weighs 54 pounds. It has been the king in the nearby mountains for several seasons. Later, a good man introduced a new goat, which weighed 3 pounds more than it. At first, they lived in peace and harmony with each other. But one day, the lighter goat stood on the top of the steep mountain road and pounced on its competitor. The competitor stood on the mound to meet the challenge, and the challenger obviously had the commanding advantage. Unfortunately, due to the violent collision, both goats died.
Now let's talk about the wonders of this topic. George abercromby, who is well-versed in raising goats and has written a book, said: "Through repeated experiments, I found that momentum is equivalent to an impact of a 3-pound weight falling from a height of 2 feet, which can just break the goat's skull and kill it." If he is right, how fast must the two goats approach each other before they smash their skulls? Can you work it out?
Puzzle of the proprietress of a wine shop
Description: No
Detailed description:
It is said that someone gave the proprietress of a wine shop a problem: this person knew that there were only two spoons in the shop, which could scoop 7 ounces of wine and 11 ounces of wine respectively, but forced the proprietress to sell him 2 ounces of wine. Clever proprietress is unambiguous. She ladles wine in the wine jar with these two spoons, and turns it upside down, and actually measures 2 ounces of wine. Can you be clever?
A question about aircraft refueling
Brief introduction: None
Detailed introduction:
It is known that each aircraft has only one fuel tank, and they can refuel each other (note that there is no tanker). A tank of oil can be used for one aircraft to fly around the earth for half a circle. Question: How many aircraft should be dispatched at least to make at least one aircraft circle the earth and return to the airport at the time of takeoff? (All planes take off from the same airport, and they must return to the airport safely. It is not allowed to land midway, and there is no airport in the middle.)
Problem
Introduction: This kind of problem is difficult. If you can't get the answer, you can't explain anything. If you think of a way to solve the problem, the answer will come out immediately. If you can't think of the train of thought, then … don't try to work it out.
Details:
1. You let the workers work for you for 7 days, and the reward is a gold bar. This gold bar is divided into 7 connected segments, and you must give them a gold bar at the end of each day. If you are only allowed to break the gold bars twice, how will you pay your workers? 2. One train leaves Beijing for Guangzhou at a speed of 15 kilometers per hour, while another train leaves Guangzhou for Beijing at a speed of 2 kilometers per hour. If there is a bird that starts at the same time with two trains at a speed of 3 kilometers per hour, it starts from Beijing, meets another car, and then returns to fly in the opposite direction, so it flies back and forth between the two trains in turn until the two trains meet. Excuse me, how long did this bird fly? 3. You have four jars containing pills, and each pill has a certain weight. The contaminated pill is the weight of the unpolluted pill +1. Weighing only once, how to judge which jar of medicine is contaminated? 4. The three switches outside the door correspond to the indoor Three Lamps District respectively, and the wiring is good. When you control the switch outside the door, you can't see the indoor light. Now you are only allowed to enter the door once, and determine the corresponding relationship between the switch and the light? 5. Why does RMB only have a face value of 1, 2, 5 and 1? 6. You have two jars, 5 red marbles and 5 blue marbles. Choose a jar at random and put a marbles in the jar at random. How do you give the best chance to choose the red marbles? What are the chances of getting the red ball in your plan?
No answer
Introduction: These questions are obviously not a test of your intelligence. The test is your reaction ability. Most of these questions have no answers, but it depends on your reaction!
Details:
1. Why is the cover of the sewer round? 2. How many cars are there in China? 3. Insert the car key into the door and turn it in which direction to unlock the car? 4. If you want to remove any of China's 34 provinces (including autonomous regions, municipalities directly under the Central Government, Hong Kong and Macao Special Administrative Regions and Taiwan Province Province), which one would you remove and why? 5. How many gas stations can satisfy all the cars in China? 6. Imagine you are standing in front of a mirror. Excuse me, why can the image in the mirror be upside down, but not upside down? 7. Why is it that in any hotel, when you turn on the hot water, it will pour out instantly? 8. How do you explain the usage of Excel to your grandmother? 9. How do you redesign and design an ATM? 1. If you have to learn a new computer language again, how do you plan to start? 11. If you plan to be rewarded within five years in your career planning, what is the motivation to get the reward? Who is the audience? 12. If Microsoft told you that we were going to invest 5 million dollars to start your investment plan, what kind of business plan would you start? Why? 13. If you could gather computer manufacturers all over the world in one office and tell them that they would be forced to do one thing, what would it be?
Draw lines
Introduction: (3 minutes -2 minutes)
Detailed introduction:
Draw 1 straight lines at 9 points, with at least 3 points on each straight line?
Weighing the ball
Description: (5 minutes -1 hour)
Detailed description:
There are p>12 balls and a balance. Now we know that only one of them is different in weight from the others. Ask how to weigh it three times to find that ball. What about 13? (Note that this question is not