The questions were adapted from the German Academy of Logical Thinking in Berlin in 1981, and 98% of the testers were unable to solve the questions
(A semiconductor design company in China had recruited employees with this question) The questions are as follows:
Logical Thinking begins:
There are five ladies in a row
All of the ladies wear the same color clothes
All of the ladies have different pets, drink different drinks, eat different food
All of the ladies have different last names
All of the ladies have different pets. All of them wear different colors
All of them have different last names
All of them have different pets, drink different beverages, and eat different fruits
Miss Qian wears red
Miss Weng has a dog
Miss Chen drinks tea
The one who wears green stands to the left of the one who wears white
The one who wears green drinks coffee
The one who wears green stands to the left of the one who wears white. > The lady in green drinks coffee
The lady who eats watermelon has a bird
The lady in yellow eats willow
The lady standing in the middle drinks milk
Miss Zhao stands on the far left
The lady who eats oranges stands next door to the one who has a cat
The lady who has a fish-eating dish eats willow next door
The lady who eats apple drinks champagne
Miss Jiang eats champagne
The lady who eats apple eats a dog
The lady who eats apple eats champagne
Miss Jiang eats bananas
Miss Zhao stands next door to the one in blue
The lady who only drinks boiled water stands next door to the one who eats oranges
Which lady keeps snakes?
The answer is in the question think hard ......................
Note: What does this question remind you of? The Germans keep fish? Hey, it's a 01 question
A2 Difficulty: ★
A manager, due to poor management, the company lost money every year, and in the end, only left with a huge amount of insurance. He decides to die, but he can't get insurance for suicide. He gets on a cruise ship and locks himself in a single room with only one small window open in the room force. Outside the window was the sea. Shortly afterward, shots were fired from his room and he killed himself. Do you know how he convinced the insurance company that it was a homicide?
Note: In the early days the guys were simple minded, who sees such lovely reasoning in posts nowadays?
A3 Difficulty ★★★
It takes place in a foolish, big womanist village in an unknown location. In this village, there are 50 couples, and each woman knows immediately when someone else's husband is unfaithful to his wife, but never knows how her own husband is. The village's strict majoritarian statute required that if a woman could prove that her husband was unfaithful, she had to kill him that day. It is further assumed that the women are agreeable to this charter, intelligent, aware of other women's intelligence, and benevolent (i.e., they never inform on women whose husbands are unfaithful). Suppose it happened in this village that all 50 men were unfaithful, but no woman could prove her husband's unfaithfulness, so that the village could go on as it had always done, happily and carefully. One morning a highly respected matriarch came to visit from the far side of the forest. Her honesty was well known, and her word was like law. She warned darkly that there was at least one flirtatious husband in the village. This fact, based on what they already know, should have only trivial consequences, but what happens once this fact becomes public **** knowledge?
Note: This question is indirectly dragged down by the fact that it is so much like an old classic question.
A4 Difficulty ★★★★★
A girl seeks her admiration for a charming boy at her mother's funeral!
After the funeral, the girl returns home and suddenly picks up a knife and stabs her sister to death - can you tell why?
The answer has to do with mental health! Everyone should pay attention to it ！！！！
Note: One of the 7 classic BT questions, it's really hard to come up with an answer if you haven't seen it
A5 Difficulty: ★
A murder occurred in a house and the deceased was a married woman. The Inspector came to the scene to observe. The coroner said that the autopsy confirmed that the deceased died no more than two hours, was stabbed in the heart by a knife and died.
The inspector found a tape recorder on the table and asked the other police officers, "Have you ever opened the recording?" From the officers all said they hadn't.
So the inspector pressed the play button, and the voice of the dead man came out of the recording tribute:
"It was my husband who tried to kill me, he always wanted to kill me. I saw him come in and he had a knife in his hand. He doesn't know I'm recording now, I'm going to half the recorder, I'm going to be killed by him soon 。。。。。。 Click." The recording is aborted at this point.
The Inspector listened to the recording and immediately told the officers that the recording was a forgery. Do you know why the Inspector was so quick to decide that the recording was a forgery?
Note: The difficulty of the questions is so much less than the neighboring version
A6 Difficulty: ★★★★☆
Late one night, three criminal cases occurred in a row in a block of apartments in London. One is a murder case, a member of the House of Commons living on the 4th floor was killed with a pistol; one is a burglary case, a famous painting collector living on the second floor of the collection of six 16th century paintings were stolen; the other is a rape case, a beautiful ballerina living on the ground floor of the thugs were raped.
After the police report, the London police headquarters immediately sent a large number of police officers rushed to the scene of the crime. According to the fingerprints, footprints and traces of struggle left by the criminals at the scene, the police concluded that the three cases were committed by three criminals separately (later confirmed that this judgment is correct)
After months of investigation, finally collected a lot of solid evidence, arrested A, B, C, three suspects. During the interrogation, the three suspects confessed as follows:
A confessed:
1, C is a murderer, he killed the House of Commons MPs for the sake of personal revenge.
2. B is a rapist because B is possessive of beautiful women.
3. Since I was arrested, of course I had to make up a confession, so I am not a very honest person.
B confessed:
1, A is a famous thief, I am convinced that it was him who stole the painting that night.
2. A never tells the truth.
3. C is a rapist.
C confessed:
1. The theft was not committed by B.
2. A is a murderer.
3. In short, I did commit a crime in this apartment that night.
Of the 3 suspects, one was the most dishonest, he told all lies, and the other's confession contained both truth and lies.
A, B, C, respectively, were made a case, after reading the statement only to hear a "boom", the police Henry fell to the ground! Smart people ah! Come and save this poor policeman! I think he will be grateful to you!
Note: There are more questions in this series than enough for a book
A7 Difficulty: ★★★★
American author Ross? Mark Denard, a man of letters who loved to study the world's famous cases, called private detective Ru? Yacha is a lone criminal philosopher, and admired the detective's talent for reasoning. The reason is that the city of Los Angeles had such a murder case, the culprit did not escape the eyes of Ru? Yacha's eyes.
Not long ago, there was a murder on Elizabeth Street, and Mr. Longfellow was arrested by the police as a suspect. It was verified that the pistol with which the murder was committed was Longfellow's, and that it bore his fingerprints. The time at which the murder was committed also proved that Longfellow had been present at the scene, and the motive for the crime was sufficient. However, his friend, Detective Emerson, who was in charge of the case, was absolutely convinced that Mr. Longfellow was no criminal! Roulet, who was a good listener, felt that there was something going on. Yacha, felt that there was something in it. After a thorough investigation, the real culprit was finally found.
Can you guess who the real murderer is?
Note: A good question
A8: Difficulty: ★★★★
Four couples - Mr. and Mrs. Vasquez, Mr. and Mrs. Jefferson, Mr. and Mrs. Parde, and Mr. and Mrs. Robert - are learning a new style of ballroom dancing. This dance must be done in pairs. At the beginning of the dance, each couple is partnered, but on the commands "X", "Y", and "Z", they exchange partners as follows:
1. When the command "X" is given, Mr. Basker and Mr. Parde exchange partners;
2. When the command "Y" is given, Lord Robert and Mrs. Jefferson exchange partners;
3. On the command "Z", Mr. Jefferson and Mr. Pard exchange partners;
4. On each subsequent command, partners are exchanged on the basis of the partners formed on the previous command.
[Question]
● Question 1 After the dance has begun, if partners are exchanged only once when the command "X" is given, which two people must form a partner the next time?
(A) Mr. Basker and Mrs. Pard; (B) Mr. Basker and Lord Robert; (C) Mr. Jefferson and Mrs. Pard; (D) Mr. Jefferson and Mrs. Basker; (E) Mr. Robert and Mrs. Jefferson.
● QUESTION 2 If, after two gags, each dancer partners with his or her spouse again; in which of the following situations could the two gags have been given?
(A) Mouthpiece "Y" follows mouthpiece "X"; (B) Mouthpiece "Z" follows mouthpiece "X"; (C) Mouthpiece "X" follows mouthpiece "X" or mouthpiece "Y" follows mouthpiece "Y" or mouthpiece "Z" follows mouthpiece "Z"; (D) Mouthpiece "X" follows mouthpiece "X" or mouthpiece "Y" follows mouthpiece "Y", but it is not possible that mouthpiece "X" was given after mouthpiece "Y". It is possible for passphrase "Z" to follow passphrase "Z"; (E) passphrase "X" to follow passphrase "X" or passphrase "Z" to follow passphrase "Z", but it is not possible for passphrase "Y" to follow passphrase "Y".
●Question 3 If the partners change partners twice after the start of the dance, the first time after the mnemonic "X" and the second time after the mnemonic "Y", which of the following must be true?
(A) Lord Basilisk was partnered with Mr. Robert; (B) Mrs. Jefferson was partnered with Mr. Jefferson; (C) Mr. Parde was partnered with Mrs. Robert; (D) only two women were partnered with their husbands; and (E) none of the men were partnered with their wives.
●Question 4 If, after two partner exchanges, Mr. Basker is partnered with Lord Basker and the second exchange takes place after the gag "Y", then the first exchange must have taken place:
(A) after the gag "X"; (B) after the gag "Y"; (C) after the gag "Z"; (D) after any gag except "X"; (E) after the gag "X"; (F) after the gag "Y"; (G) after the gag "X"; and (E) before the first exchange. (C) after password "Z"; (D) after any other password except password "X"; (E) after any other password except password "Z".
●Question 5 If, after two partner swaps, Mr. Jefferson partners with Lord Basilisk and the second mnemonic is "Z", then the first mnemonic should be:
(A) "X"; (C) "Z"; (D) any mnemonic other than "Y"; and (E) any mnemonic other than "Z".
●Question 6 If, after the dance begins, partners are exchanged three times in the order of the mnemonic "Z", "X", and "Y", which of the following must exist after the third mnemonic?
(A) Mr. Parde was partnered with Mrs. Jefferson; (B) Mr. Parde was partnered with Lord Robert; (C) Mr. Basker was partnered with Mrs. Basker; (D) Mr. Basker was partnered with Mrs. Jefferson; (E) Mr. Basker was partnered with Lord Robert.
Note: What a long title.
A9 Difficulty: ★★★★★
There are two 1-pound bottles of wine (assuming they are filled to 1 pound) and an empty three-two cups, how can five people drink them evenly (without the aid of another container or a diagonal solution to half)?
Note: Split the wine question, choose one to do
A10 Difficulty: ★★★★
ABCDE Five people come to a French restaurant. There are N things on the menu, but the names are all in French. These 5 people just blindly order one thing each (can be the same).
The waiter serves it up and doesn't explain to them what's what or what dish was ordered by whom. These 5 people then had to reason on their own. For example, if only AB two people ordered the same dish, and served up 5 pots of food are vxyxz, then they can 5 dishes in the only same two pots of x is what. If AB ordered the same, CD ordered the same, and what was brought up was yyxzx, then they could reason that the pot ordered by E was z.
After 5 people went to this restaurant three times, they finally got it exactly right what each of the N dishes on the menu was. Q: What is the maximum number of N?
A11 Difficulty: ★★★★
On a hot summer's day, A and B drove out to have fun, and on the way A panicked and said the car broke down, and asked B to get out and help, and B was killed by A. In order not to arouse suspicion, A immediately ran to the police station to report to the police, saying that they drove out to have fun who knew that halfway there came two robbers, who killed B. The officers rushed to the scene to find that B had a clear stab wound on the chest. The officers arrived at the scene to find B's chest has a clear knife wound, it is clear that the murderer is with a sharp knife stabbed to death.
At this point Detective F (Hattori Heiji) notices a puddle of water stains at the front wheels of the car, he enters the car and takes a closer look, when he walks out he inadvertently notices shards of eyeglasses littered all over B's side, and then he shouts out to A, "The murderer is you!"
"It can't be, physically I'm no match for him, so how can you say I'm the murderer? Besides, where would I have the chance to kill him?" A sophomoric defense.
"Your chance is--"
After Detective F explained A was taken to the police station, ask A how he found a chance to kill B it it
A12 Difficulty: ★★★★★★★☆
There are five athletes A, B, C, D, and E competing in a diving competition. In the stands, A and B are making predictions about their ranking order.
A says: The order of the places will be A, B, C, D, E.
B says: The order of the places will be D, A, E, C, B.
The result of the competition shows that A's prediction is wrong. He did not guess the correct place of any of the athletes, nor did he guess the order of any of the pairs of athletes with neighboring places.
B got his prediction partially right. He guessed the correct ranking of 2 athletes; at the same time, he guessed the order relationship of two pairs of athletes with adjacent rankings.
Based on the above information, please come up with: the actual ranking of the 5 athletes A, B, C, D, E.
To avoid confusing people, I only ask you to write the ranking order. The process is exempted~~
A13 Difficulty: ★★★★★★
A few days ago only opened the gold box of Ara C, gleefully towards the entrance of the cave, ready to go home to enjoy this hard-earned wealth. But no matter how hard he looked, he couldn't find the original entrance. Arapaho finally reached the end of the road, the dark cave seems to see the skeletons of many ancestors, and then he saw three heavy stone doors, is the legendary "three light door".
The three stone gates are engraved with some words:
Sun Gate: "This is the door to freedom"
Moon Gate: "This is not the door to freedom"
Star Gate: "Moon Gate is not the door to freedom"
Arakan remembered the golden old man's note that the gold chest contains the key to the Three Gates of Light but it will disappear if it is used only once and that the three gates have the key to the Three Gates of Light, which is the key to the Three Gates of Light. At least one of these three door statements is true and at least one of them is false. Can you help Ara C get through this one?
A14 Difficulty: ★★★★☆
Early last year, I as an accompanying reporter with the U.S. Geological Expedition Team in the Grand Canyon found the body of an old Chinese man, in the diary he was carrying recorded an amazing discovery, but the diary did not record the exact location, in the old man's luggage, in addition to some essential props for wilderness survival, we found the following
1, half a piece of silk, which is written with a few lines of Chinese characters, "tenderness is like water, good times are like a dream, bear to look after the magpie bridge to return to the road, the golden wind and jade dew a meeting, will be better than countless on earth."
2. A sketch of a reed, broken at the top third.
After a few thoughts, I finally understood the old man's hint, which is probably the old man is afraid of their own forgetfulness, but do not want others to know the memo made it. So we buried the nameless old man and embarked on a new journey full of temptations and challenges.
A15 Difficulty: ★★★
Officer Nishizawa's best friend Aoki is a baseball coach.
On this day, Aoki came to the police station in a hurry, reporting the incident with a bitter face and telling what happened.
"I came home late today, and it was almost 10 o'clock when I arrived home. After entering the door I found my daughter Keiko lying on the table, at first I thought she was asleep, called several times and did not see the answer, approached and realized that she had ...... died ......."
Nishizawa police officers immediately rushed to the scene, found on the table and drank half of the Coca-Cola. After laboratory tests proved that it was mixed with cyanide. On the table, there were several pieces of letterhead scattered, one of which contained half a glass of Coca-Cola mixed with cyanide. The handwriting of the pen on that letterhead is very clear.
"Where was this listen of Coca-Cola originally placed?" Cesar asked. "It was in the kitchen refrigerator." Aoki replied, "My daughter loves to drink cold Coca-Cola, so my refrigerator is always stocked with a large amount of Coca-Cola, who would have thought that someone would use it to poison Keiko and kill her ......" Nishizawa opened the refrigerator and looked at it, and then went back to Keiko's boudoir. He picked up a piece of letterhead on the table and looked at it, asking his assistant, Saburo Akechi, "Have these letterheads been identified?" "Yes, they have been authenticated, the handwriting and fingerprints on them are all Keiko's, and the letterhead is filled with verses about lost love." "Aoki, is your daughter in love?" Nishizawa asked. "Yes," Aoki replied, "Since I don't agree with her dabbling in love at a young age, she broke up with her boyfriend a few days ago." Nishizawa pulled out the piece of letterhead pressed under the Coca-Cola again and examined it for a moment, then asked, "And the listening Coca-Cola was always pressed on this letterhead?" "Yes, no one has touched it." Aoki replied. Nishizawa thought for a moment and judged, "This Coca-Cola was not taken by Keiko from the refrigerator, but was used by the criminal to make her drink to death!"
May I ask why Officer Nishizawa made this judgment?
A16 Difficulty: ★★★
A homicide has occurred in a cigar and tobacco factory. In a room on the fifth floor of an apartment, an accountant at the cigar factory was stabbed in the back and died on his writing desk. The body was found at about 4 p.m., when a large cigar sitting in an ashtray on the desk was still burning, leaving a 1-centimeter-long ash on the front end of the cigarette.
"Judging by the length of the ash, it had been less than 10 minutes since the cigar smoke was lit."
"So that means the time the criminal escaped after killing the accountant was around 3:50." The criminal police examined the cigar smoke.
However, the autopsy showed that the time of death was around 1 p.m. and the murderer was arrested a day later. He confessed that he left the scene of the crime at 1.30 pm. After that, he had a solid alibi. If so, how could the murderer have escaped by lighting a cigar 10 minutes before 4 p.m., when the body was found? The criminal police wondered, but the mystery of the case was immediately solved when they discovered a celestial telescope sitting beside the writing desk.
"Good, the front of this celestial telescope was facing a glass window in a southwesterly direction, so that the murderer's modus operandi could be recognized." Well, the truth is ......
A17 Difficulty: ★★★★
Three sailing enthusiasts*** have a dinghy. They wanted to make an arrangement so that each ________ could pick up the dinghy and use it at any time without having it stolen by someone else. To do this, they lock the dinghy to the shore with three locks and a chain. Each person has only one key, but can open the lock with his own key without waiting for the other two to come with their keys.
How did this ingenious arrangement work?
2. I bought a book in an antique bookstore in Leipzig that has 200 pages. On pages 3 to 12 there were 10 pages with notes of interest to me, so I took them down, leaving 190 pages. But pages 56 to 75 ****20 pages also had important notes on them, so I took them down again.
How many pages are left in the book?
A18 Difficulty: ★★★★
A jewelry company employs a group of security guards for the night shift, and Hubert is one of them.
(l) The shifts are on a rotational basis. It has been less than 100 days since Hubert's first shift.
(2) Hubert's first and most recent shifts fell on the only two Sundays he was on duty.
(3) Hubert's first and most recent shifts were on the same day in different months.
(4) Hubert's first and most recent shifts were on the same number of days in the same month
In which of the 12 months of the year was Hubert's first shift?
A19 Difficulty: ★★★★★
The five girls taught by music teacher Lord Thomas are about to graduate, and she wants to send each student a bouquet of flowers to congratulate them. The florist suggested: "Ma'am, I think you should buy five bouquets of roses, with eight blooming flowers in each bouquet, that's really beautiful. There are yellow, pink, white and red roses, which color would you prefer?" "Sir, it seems to me that all four colors should be in all five bouquets, is that possible?" Mrs. Thomas demanded.
Thanks to the florist's careful combination, the result was satisfactory.
A. The bouquet of roses that Alice got had more yellow flowers than the other three colors combined;
B. The bouquet that Barbara got had fewer pink flowers than any of the other colors;
C. The bouquet that Claire was holding had the same total number of yellow and white flowers as the total number of pink and red flowers;
D. The bouquet that Diana was holding had the same number of yellow and white flowers as the total number of pink and red flowers;
E. The bouquet that Diana was carrying had the same number of yellow flowers as the total number of pink and red flowers. In the bouquet held by Diana, there were twice as many white flowers as red flowers;
E. In Effie's bouquet, there were as many red flowers as pink flowers.
Knowing that there are 10 flowers of each color, and that the total number of flowers is 40, how many flowers of each color are in the bouquet in each girl's hand?
A20 Difficulty: ★★★★★
A farmer is suffering from an incurable disease and wants to die. But if he kills himself, his family will not get the life insurance money.
So, in order to make it obvious that it was a homicide, he shot himself in the head with a miniature pistol and cleverly concealed the pistol in the yard while the whole family was out. He thought that as long as the murder weapon was not placed next to the body, it could be recognized as a homicide.
When the body was found, the pistol was found in front of a sheep pen 15 meters away from the body. However, if a gunshot to the head would have resulted in immediate death, the farmer would never have thrown the pistol 15 meters away on his own, much less staggered over to it and thrown it there.
So what means were used to hide the pistol in front of the sheep pen?
But the goat didn't take a step out of the pen.
Note: Another case of suicide by disguise
A21 Difficulty: ★★★★
There was a strict discipline in a military school where cadets were not allowed to go out without permission. Once a cadet from a certain spot went out without permission. When the instructor learned of the incident, he questioned each of the eleven cadets in the class
The results of the questioning were as follows:
Akiyo Akiyama said, "The one who went out without authorization was Akiyo Kume."
Inoue said, "It was me who went out."
Uchie says, "Inoue is telling a lie."
Egawa says, "Both Inoue and Akiyo Akiyama are lying."
Ichiro Sato says, "It was Uchie who went out without authorization."
Jiro Sato said, "I didn't go out and neither did Uchie."
Saburo Sato said, "There is not -one- of the people with the name Sato who went out without authorization."
Kume Akiyo said, "Those who went out without authorization were either Uchie or Ekawa."
Ichikawa Akiyo said, "Besides me, the other two people named Akiyo are lying."
Kondo says: "Of the three people named Sato, only one told the truth."
Sakai said: "Two of the three named Sato told the truth."
Later, according to a source, at least seven of the eleven people who answered told lies. Based on this clue, can you tell who went out without authorization?
A22 Difficulty: ★★★★★
One day, when Dr. Riddles was walking on the Island of Lies, he encountered three more islanders, and Botu first asked one of them, "What tribe are you from?"
The man replied, "Of the Honest Clan."
The Doctor then asked the second man, "What tribe are you of"
"I am of the Lying tribe," replied the second man.
The Doctor then asked again, "Is it true that this man who just answered my question is of the Honest Clan?"
"Yes", replied the second man.
The Doctor then asked the third man, "What race are you of?"
The third man replied, "Of the Honest Clan."
The Doctor then asked, "What tribe is the first man who answered my question?" .
The third man simply replied, 'Of the Two-Faced Clan."
Ask what clan each of these three men is of?
A23 Difficulty: ★★★★
After visiting the island of lies for a while, Dr. Riddle left this island to visit the neighboring island of Two Faces. Although the inhabitants of Two Faces Island are all two-faced (speaking in true sentences and false sentences, and interacting between true and false), there are three subdivided branches within the Two Faces. Those in the first branch speak the truth in the first sentence and the lie in the second. In the second branch, the first sentence is false and the second sentence is true. The third branch of the entry, the first sentence to say true and false as you wish, sometimes true, sometimes false.
When the islanders on both sides of the island heard of the Doctor's visit, a representative of each of the three branches went to receive him. The luncheon was held around a round table. In order to find out which branch each of the three representatives belonged to, the Doctor left his seat before the meal, and asked each of the three, in clockwise order, the following three questions.
(1) What is your name? (2) Now what is the name of the person on your left (3) Which branch is he from?
To these three questions, the three men answered as follows:
The first man: (1) Petro, (2) Roderick, (3) of the second branch.
The second man: (1) Roderick, (2) Kehota, (3) of the first branch.
The third man: (1) Petro, (2) Roderick, (3) of the second branch.
May I ask which branch each of these three men is from, what they are called, and whether the first sentence of the man from the third branch is a truth or a lie?
A24 Difficulty: ★★★★★
A, B, C, D, E, F and G are arguing:What day of the week is today?
A:The day after tomorrow is Wednesday.
B:No, today is Wednesday.
C:You are all wrong, tomorrow is Wednesday.
D:Nonsense! Today is neither Monday, nor Tuesday, nor Wednesday.
E:I'm sure yesterday was Thursday.
F:No, you've got it backwards, tomorrow is Thursday.
G:Anyway, yesterday wasn't Saturday.
In fact, only one of the seven people got it right.
May I ask who got it right? What day of the week is it?
A25 Difficulty:★★★★★
A traveler has come to the border area between A and B. He wants to know whether he is in A or B. He wants to find someone to ask.
People in both A and B only nod or shake their heads to say yes or no. People in A are sincere and nod their heads to say yes and shake their heads to say no, while people in B are the opposite of people in A.
Now, the traveler comes to the border area of A and B and wants to know whether he is in A or B. He wants to ask a person.
Now how does a traveler know whether he is in A or B by asking a person a question?
A26 Difficulty: ★★★★
A, B, C, D, E, F, G The ranking of A, B, C, D, E, F, and G in terms of place in the results of the game is as follows (where there is no tie for place):
1) E comes in second or third place.
2) C did not finish four places higher than E.
3)A is lower than B.
4)B is not two places lower than G.
5) B is not first place.
6)D is not three places lower than E.
7)A is not six places higher than F.
Only two of the above statements are true, which are they? Find out their rankings.
There is a time limit of 5 minutes to do these questions.
A27 Difficulty: ★★★★☆
A professor who teaches logic has three students, and all three are very smart!
One day the professor gave them a problem. The professor put a slip of paper on each person's head and told them that each person's slip of paper had a positive integer written on it, and that the sum of two numbers was equal to the third! (Each person can see the other two numbers, but not his or her own)
The professor asked the first student: can you guess your own number? Answer: No;
Ask the second one, no;
The third one, no;
Ask the first one again, no;
The second one, no;
The third one: I guessed it, it's 144!
The professor smiled with satisfaction. Can you guess the number of the other two, please? Please give your reasons!
A28 Difficulty: ★★★★★
There are five relatives, A, B, C, D and E. Four of them each tell a true story as follows:
1) B is my father's brother;
2) E is my mother-in-law;
3) C is my son-in-law's brother;
4) A is my brother's wife.
Each of the people mentioned above is one of these five (e.g., when someone says "B is my father's brother", you can assume that "my father" and "my father's brother" are A, B, and C). " are one of the five persons A, B, C, D, and E)
Q: What is the relationship of each of these five persons?
A29 Difficulty: ★★★★
This is a very famous German question, which mainly examines the comprehensive ability of an individual, and I think it's a very good question, so I'll share it with you:
One day, Mr. A and Mr. B were walking along the road together, and they met Mr. B's three acquaintances, X, Y, and Z.
Mr. A asked Mr. B about them: "How old are the three of them?"
B Jun thought about it and said, "Then I'll test you: the sum of their ages is the sum of our ages, and the multiplication of their ages equals to 2450."
A Jun did some math and said, "I still don't know!" .
Jun B laughed at this and said, "Wow! Then I'll give you one more condition - all three of them are younger than our friend, C Jun."
Mr. A heard this and said, "Oh, I see."
Finally, Jun C is asked what his age is.