1001 brain teasers that Harvard and Cambridge students are doing

Chapter 2

Intellectual arena

00 brain teasers

What is the secret of human longevity?
It was raining, and everyone was in a hurry to go home, but there was one person who walked slowly (he didn't hold an umbrella).Someone asked him why he didn't hurry home, and he only said one word, which made the man faint.May I ask what he said?

There is a candle and a kerosene lamp on the table, which one to light first?
There is neither a bridge nor a boat at the Yellow River ferry.Ruan Xiaoer said to Shi Qian: "Don't look at how wide the water is, I crossed it five times in one go this morning!" Shi Qian said, "You went home after swimming?" Ruan Xiaoer said: "Of course! Shi Qian said: "You bragging!" Ruan Xiaoer is a well-known hero in the water in Liangshan. It's not that Shi Qian doesn't know, but why doesn't he believe Ruan Xiaoer?
Keep breathing, don't stop breathing.

"What's the hurry, it's not raining yet!"

matches.

Because after crossing the Yellow River five times, people should be on the other side of the river, and it is impossible to go home.brain teaser

Why do people close their eyes when they are dead?
5只鸡5天生了5个蛋。100天内要生100个蛋，需要多少只鸡？
Xiao Ming eats a master every day, is he a monster?
How did the president of the United States get into the White House?

Under the same conditions, put two cups of milk at different temperatures in the same refrigerator, which one will cool faster, the one with the higher temperature or the one with the lower temperature?

A with high temperature B with low temperature is as fast as C
Because opening your eyes will scare people to death!
Still only need 5 chickens.

Eat Master Kong instant noodles!

Entered through the gate.

c.The speed of cooling is not determined by the average temperature of the liquid, but by the temperature difference between the liquid and the environment.When the hot milk is cooled rapidly, this temperature difference is relatively large, and during the entire cooling process before freezing, the temperature difference of the hot milk is always greater than that of the cold milk.The hotter the surface, the more heat is dissipated from the surface, and the faster it cools down.This is the Mpemba phenomenon.brain teaser

Xiaohua's grandfather has 7 sons, and each son has a younger sister. May I ask: How many children does Xiaohua's grandfather have?

11+2=1 right?

What kind of cloth can't be bought at the cloth store?

Xiao Wang bought a new stereo, turned on the power, and played the CD, but there was no sound. What went wrong?

There is a jug with 900ml of water and two empty cups, one can hold 500ml and the other can hold 300ml.May I ask: How should the water be poured so that each cup has exactly 100 ml? (Note: It is not allowed to use other containers, and it is not allowed to mark the cups.)
8, the daughter is the youngest.

right! 11 o'clock plus 2 o'clock is 1 o'clock!

Songtsan Gampo.

power cut.

Fill both glasses first, then pour out the remaining water in the jug.Then pour all the water in the 300ml cup back into the kettle, pour 300ml of water from the large cup into the small cup, and pour the 300ml of water back into the pot, then pour the remaining 200ml of water in the large cup into the small cup. cup.Fill the large cup (500ml) with water from the jug so that only 100ml remains in the jug.Then fill the small cup with water from the large cup (only pour 100ml to be full), then pour out the water in the small cup, and then pour 300ml from the large cup to the small cup. After drinking 100ml, pour out the water in the small cup, and finally pour the remaining 100ml of water in the kettle into the small cup.This way there is exactly 100ml of water in each cup.brain teaser

The pony can't do light work, one foot on the egg, but the egg won't break, why?
What book can't be bought in the bookstore?

What color are the teeth of black and white babies?

Xiao Han accidentally swallowed a coin into his stomach, why did he take it out after 10 years?

During a party, a classmate came up with a difficult problem to test other students.The classmate took out an egg and said, "Who can stand this egg on the table?"

The students stood on the left and on the right, but they couldn't stand up, so they had to ask this classmate for advice.And he stood up the egg easily.Do you know how he did it?

The other foot is on the ground.

Secretary.

Newborn babies have no teeth.

Don't rush to use it.

He picked up the egg, looked at it against the light, and then knocked it on the table, breaking the eggshell underneath, and the egg stood firmly on the table.brain teaser

Juanjuan and her mother are both in the same class. Why?
Lin Lin sleeps in a tent while camping, and wakes up to see the sky full of stars, what will he think?
There is a small tree that has not been uprooted or buried by things. After a few years, the small tree disappeared. What happened?

What is unknown to the world, what you do not know and I know?
There are eleven balls of the same size in a transparent soft plastic tube with open ends, six of which are white and five are black, as shown in the figure below.The inner diameter of the entire section of plastic tube is uniform, and only one ball can barely pass through.How do you get the black ball out without removing the white ball first and without cutting the plastic tube?
One is a teacher and the other is a student.

The tent was stolen.

Small trees grow into big trees.

There is a hole in the sole of the shoe.

As shown below.Bend the soft plastic tube so that the nozzles at both ends are docked with each other, let the four white balls roll over the joint and into the nozzle at the other end, and then separate the two ends of the plastic tube to restore the original shape, and then the black ball can be taken out .

Brain teasers

In the world, did men come first, or women first?Why?
What soup is the freshest?
A girl is taking a shower, and a boy breaks in. Where does the girl most want to hide?
What is something smaller than bacteria?
Where is the densest bullet on the battlefield?

The caterpillar's mother gave the caterpillar a difficult task: to crawl from one side of a piece of paper to the other.The caterpillar thinks: Every piece of paper has two sides and a closed curved edge. If you climb from one side to the other, you have to pass through this edge without any fulcrum. If you want to pass through this edge, even if I The body will also be in danger of "falling off the cliff".It seems that you can't force your way, you need to think of some skills.

Do you know what the caterpillar came up with?
man.Because it's called Mr. Man.

"Fish" soup and "mutton" broth.

Boy's eyes.

Bacteria children.

On the ammunition carrier.

Roll up one end of the paper slightly against one side of the paper, and the caterpillar will be able to crawl smoothly from one side of the paper to the other.Of course, to accomplish this task the caterpillar needs help from others.brain teaser

The wing of a plane broke suddenly. Wang Jun, who was flying the plane, did not bring a parachute, but he was not afraid. Why?
A squad of paratroopers was training for parachute jumping. The squad leader said that after jumping out of the cabin, the parachute could only be pulled out after counting to 30. As a result, everyone else landed safely, and only one person died unfortunately. Why?
Xiaowei's mother knows that Xiaowei is going to study abroad next year, why can't she sleep because of this incident since yesterday?
An eminent monk died at the same time as the butcher, why did the butcher ascend to heaven before the eminent monk?
In the desert, 7 cacti of different sizes stand in a row, and there is a shooter who is going to shoot and kill the heads of 4 cacti and the roots of 3 cacti.May I ask: How many shots does he need at least?
The plane didn't take off.

He stutters.

Tomorrow is New Year's Day.

Put down the butcher knife and become a Buddha on the spot.

At least one shot is required.Because the cactus may be arranged in a straight line in addition to being neatly arranged in a straight line, the bullet can pass through the head of the low cactus and the root of the high cactus at the same time.brain teaser

Old Zhou thought as he walked, "It would be great if I could be with women all day long!" It didn't take long for his dream to come true.Do you know what's going on?
Where are the most roads leading to in the world?
The football game has just started, and everyone knows the score. Why?
Lily drew a pig on paper, do you know where she started?

There is an ordinary coin, Coco tossed a total of 30 times, each time it is heads.Now Coco wants to toss it again. Do you know the probability of the head?

Lao Zhou had a car accident, and nurses took care of him every day.

Rome.All roads lead to Rome.

0:0
Drawn from the tip of the pen.

1/2.No matter who throws it, and no matter how many times it is thrown, the probability of only heads and tails will not change.Don't let the number of tosses lead you into a trap.brain teaser

How can I avoid being bitten by a dog?

When did you become more sure that you were Chinese?

What mouse walks on two legs?
One day, the hunter went out to hunt and did not return home until dark.His wife asked him: "How many beasts did you kill today?" The hunter said: "9 were without tails, 8 were half-sized, and 6 were without heads." What does it mean.

Do you know how many beasts the hunter killed?
Run faster than a dog.

When in a foreign country.

mickey mouse.

None hit. 9 without tail is 0, half of 8 is also 0, 6 without head is still 0, so the hunter did not hit the beast.brain teaser

There is a thing that grows beards when it matures, what is it?
What is the top of the sky?
On birthdays, the birthday cake is often cut.Now there is a big cake, if you want to cut it into 3 pieces with the same shape and size for 8 knives, and you are not allowed to change the position of the cake.How should I cut it?
corn.

is one".

Holding a knife and scribing on the surface of the cake, you will never be able to find the correct way to cut it. Think full of imagination and let the sight shift from the plane to the space.The cutting method is shown in the figure below.

Brain teasers

Xiaodong fell asleep in class, but the teacher didn't talk about him, why?
What thief can be executed immediately after being caught?

The elder brother bought 3 bags of rice and the younger brother bought 2 bags of rice. They put the rice in a big bag when they got home. How many bags of rice do they have now?
Do you know how to read this poem?

open
mountain full
Momoyama apricot

good view mountain
Come to see the mountains

Lishan Monk Mountain Keshan
Mountain Road Turning to Cliff

The teacher didn't see it.

squid.

1 bag of rice.

The mountain road in the mountain turns to the cliff, and the mountain guest comes from the mountain monk mountain.The mountain guest has a good view of the mountains, and the mountains are full of peaches and apricots.brain teaser

Xiao Ming scored 100 points in the test, why did he cry?
There is a rooster laying eggs on the roof, do you think the eggs will fall from the left or the right?

Divide 8 in half, how much?

Do you know what's wrong with sleeping in class?

What is the mechanism that thieves are most afraid of touching?
A went on a trip, and B asked him where he had been, and he said: "Oasis on the sea, the wind is calm; the Milky Way Ferry, the giant ship starts; a place that is neither hot nor cold, has four seasons of bonuses." Where have you been.Inspired by A, B finally guessed the 6 cities that A has visited.

Guess which 6 cities are these?

Happy to cry.

Roosters don't lay eggs.

0.

It's not as comfortable as the bed.

public safety agency.

Carefully analyze and understand each known condition, so that the thinking can proceed smoothly until the result is derived.The six cities are Qingdao, Ningbo, Tianjin, Shanghai, Wenzhou and Changchun.brain teaser

Where is the place that people can never climb?

When learning what characters, people always learn foreign characters first and then learn their own characters?

After half a year drifting in the vast sea, what do you want to do most when you set foot on land?
A carpenter testifies about a car accident he witnessed.

Asked by the judge how far he was from the scene of the accident, the carpenter replied: "3377 meters."

"What?" asked the judge, "How can you be so sure about that distance?" The carpenter replied, "Well, I measured the distance because I knew some idiot would ask that question."

the top of his head.

When learning to write numbers, first learn 1, 2, 3, which are Arabic numerals.

The other foot also set foot on land.brain teaser

If three of your classmates come to your house and you want to hide an apple on the table for them to find, where would you hide the apple so that they can't find it?

What drink can turn a person into a ghost?

That day Zhang San came to visit his relatives, it was getting late, and it started to rain at some point, so Zhang San planned to stay.But the relatives didn't want to keep him, so they wrote a sentence on the paper:

Stay away when it rains, stay away when it rains
After Zhang San read it, he understood what he meant, but he didn't make a sound, and added a few punctuation marks:
On a rainy day, stay with guests, stay with people? Stay!
The relatives saw that the meaning of this sentence was completely reversed, so they had nothing to say, so they had to arrange accommodation for Zhang San.

In addition to Zhang San’s marking method, there are three other marking methods in this sentence, which make it into question, question and answer, and statement. Can you mark it out?
in stomach.

drink.

On a rainy day, stay away from guests, or not? (interrogative sentence)
On a rainy day, stay away, stay away? No stay! (Question and answer)
On rainy days, guests stay, days stay, people don't stay. (declarative sentence) brain teaser

A primary school student wanted to jump over a river two meters wide, but failed several times.But later, he achieved his goal without using any tools.Do you know what good method he used?
Why do policemen wear white belts?

Why does my new sock have a hole?

Yoyo is sick and needs injections every day.She is afraid of pain, and every time she gets an injection, she says her butt hurts so badly.On this day, her mother accompanied her to get an injection again, but this time she said that her butt didn't hurt at all.Why is this?

King Solomon had a beautiful daughter, and princes and marquises from many surrounding countries came to propose marriage.In order to test the wisdom of the suitor, King Solomon drew a pattern composed of many triangles and asked the suitor to count how many triangles there are in the pattern, and the one who counts the right number can marry the princess.

Can you count how many triangles are in the pattern?
Wait until you grow up.

Pants will fall down without a belt.

How to wear it without holes.

It was the arm.

There are a total of 31 equilateral triangles in the pattern drawn by King Solomon.brain teaser

Xiao Qu said that he could wipe out the room and all the toys in the room within one second. Is this possible?
Alcoholic drinking too much alcohol will hurt your health, why don't you drink it?

Why do swallows fly to the south for the winter?

As shown in the picture below: There is a small grass altar between A and B, and there is a path on both sides of the grass altar.Xiaoming and Xiaojun start from point A at the same time, Xiaoming walks on the left path, Xiaojun walks on the right path, who will reach point B first at the same speed?
Close your eyes.

sad.

Walking over is too slow.

Arrive at the same time.Both trails have the same distance.As shown in the figure below: the sum of the distances of each section of line [-] is exactly equal to the distance of line [-].

Brain teasers

Xiao Cao went to participate in a joke-telling competition, and along the way Xiao Cao kept covering his mouth with ice cubes, why?
What ball do you like to let it move?

Ou Ou is sick, injection or medicine, which one is more painful?
Why do snakes shed their skin?

Why is there a podium in the classroom?
There are 16 trees planted on an open land, and they form 12 rows with 4 trees in each row, as shown in the figure below. In fact, these 16 trees can form 15 rows with 4 trees in each row.Do you know how to plant?
I'm afraid the joke is not fresh anymore.

eyeball.

Ou Ou is more painful.

The skin is itching.

Improve the status of teachers.

According to the planting method shown in the figure below, 16 trees can form 15 rows, with 4 trees in each row.

Brain teasers

A professor has a younger brother, but the younger brother denies having an older brother. Why?
Who is the person who only works one day a year and is not afraid of being fired?

Why do foreigners come to China to visit the Great Wall?
Can you cut the mooncake into 5 pieces with only 16 cuts?

This professor is female.

Santa Claus.

There is no Great Wall in foreign countries.

As shown below.

Brain teasers

Tiantian picked up 1 yuan on the ground and took it to the school to give it to the teacher. After the teacher asked about the situation, he returned the money to Tiantian.Why did the teacher do this?

The fecundity of mice is very amazing. It is said that a mother mouse gives birth once a month, giving birth to 12 pups in one litter.The pups are fertile when they reach two months of age.Assuming that a newborn mouse is raised now, how many will it become in 10 months?

Which one has contributed the most to the country, the Golden Bell Award, the Golden Horse Award, or the Academy Award?
Sissy borrowed a 100-page book from the library.When she got home, she found that the 20-25 pages she wanted to read had fallen off.So, do you know how many pages are left in the book Sissy borrowed?
Daily money is picked up at home.

Still one, a mouse cannot give birth to young mice.

Golden Bell Award, serve the country faithfully.

92 pages.There are 20 pages from the 25th to 6th pages, so subtract 100 from 6 to get 94 pages, so the calculation is wrong.Paper has two sides, so it is impossible to peel off only one side.Since page 20 fell off, page 19 must also fall off.In the same way, since the 25th page has fallen off, the 26th page on the back must also fall off thereupon.Therefore, pages 19 to 26 should be missing, a total of 8 pages.brain teaser

There is a country where accidents happen every day, and all accidents that happen that day will be published in an evening newspaper called "Event News" in the country.One day, miraculously, nothing happened in the country, but the newspaper still published the accident.After all, what other unexpected news can be reported by this newspaper that specializes in accidents?

Xiaosong watched a cultural performance at night, why did an actor always turn his back to the audience?

Who likes to be literal?

Some are sold, some are not bought, and a lot are sold every day.

There are 6 hats, 3 of which are red, 2 are blue, and 1 is yellow.A, B, C, and D stand in a row with their eyes closed. A is at the front, B is next, C is third, and D is last.The teacher puts a hat on each of them. They don't know the color of their own hat, but the people behind can see the color of the hat of the person in front.When the teacher asked Ding first, Ding said that he could not judge the color of the hat he was wearing.After hearing Ding's words, B also said that he didn't know what color hat he was wearing.B thought about it, and shook his head, not knowing what color hat was on his head.After listening to what they said, A smiled and said that he knew what color hat he was wearing.Do you know what color hat A is wearing?
Surprisingly, nothing happened.

Bandleader.

bookworm.

threshold.

The hats worn by A, B, and C have the following 3 possible colors: red red red, red red blue, red red yellow, red blue yellow, red blue blue, blue blue yellow.Ding who stood at the end couldn't tell what color hat he was wearing, which meant that the three people in front must not be blue, blue and yellow, otherwise he could deduce that he was wearing a red hat.The colors of the hats worn by the two people in front of C may be: red-blue, red-yellow, red-red, blue-yellow, and blue-blue.But he couldn't tell the color of the hat he was wearing, so the two people in front couldn't be blue or blue or yellow.Because if it is blue, blue and yellow, B can deduce that he is wearing a red hat.According to the reasoning above, the colors of A and B's hats can only be red-blue, red-yellow, and red-red. If the color of A's hat is blue or yellow, B will be able to deduce that his hat is red.Since B did not introduce the color of his own hat, the color of A's hat must be red.brain teaser

Is the sky bigger or the moon bigger?
If you had wings what would you do?
Tom should have sailed the yacht to the Red Sea, but it ended up in the Black Sea, why?
Cosmetics can make a woman's face beautiful, but who's face will be very ugly?

During the First World War, the outstanding German female spy Marie was ordered to collect French confidential information.

General Moore was a French politician.Through some public occasions, Mary met the general and became his friend.Mary knew that the general would often bring home important government documents and lock them in safes.

One day, Mary came to the general's house as a guest. Taking advantage of the general's unpreparedness, she put sleeping pills in his water glass. The general fell asleep soon after drinking it.

Mary took the opportunity to sneak into the general's study room, and it was almost 2 o'clock at night.The safe is next to an old big clock. The password is 6 digits, but the exact password cannot be known.

Mary searched the entire study room, but could not find any trace of the password. She was extremely disappointed. Suddenly, Mary noticed something strange. The hands of the big clock in the room were the same as when they entered the door, still staying at the position of 9:35:15. , So he cracked the 6-digit password and successfully stole the confidential information of France.

How did she find the code?
Of course it is a month, 30 days is a month.

Go to the doctor.

He is colorblind.

The man who pays.

The secret is in the big clock.After Mary sneaked into the study, she searched for most of the day, but the clock was still at 9:35:15, so she had an idea and arranged the numbers of hours, minutes, and seconds as 93515. However, there were only five digits, and there was still a gap of one 9, which is the password of the safe.brain teaser

Xiao Wang met a girl, fell in love with her at first sight, and learned that she didn't have a boyfriend, why is Xiao Wang still depressed?
Someone bought a car and sold it for a higher price two years later, why?
Xiao Li ran 100 meters in ten seconds, Xiao Ma ran in 11 seconds, why did Xiao Ma get the gold medal in the end?
Recruits A, B, C, D, E, and F are lining up and running to the training ground. It is known that: F is not in the last row, and there are two people between him and the last person; E is not the last person; There are at least four people in front of A, but he is not ranked last; D is not ranked first, but there are at least two people behind him; C is not ranked first, nor is he ranked last.

May I ask: How is the order of the 6 of them arranged?

She is married and has a husband.

Antique car.

Xiao Li did not participate in the competition.

The order in which recruits line up is: E, C, F, D, A, B.brain teaser

A fire broke out in one place. Although many people were fighting the fire, no one called the fire alarm. Why?
If Zhuge Liang was still alive, how would the world be different now?
Yunyun often beats people in a school, but he becomes an outstanding student in the school, what is going on?

Xiao Zhang's driver rushed down the mountain quickly, but did not hurt anyone. What's going on?

During the exam, Weiwei copied all Xiao Jun's papers. Why did Xiao Jun get 100 points but Weiwei got no points?
A frog fell into an 18-foot-deep well.It climbs 6 feet during the day and falls 3 feet at night.At this rate, how many days will it take to climb out of the wellhead?
There was a fire at the fire station.

One more person.

So Yun went to boxing school.

Xiao Zhang's driver did not drive.

Weiwei even copied Xiao Jun's name.

Many careless people are likely to come up with an answer of 6 days.Their thinking is: the frog climbs 6 feet during the day and slides down 3 feet at night, so it climbs 3 feet a day on average; the well is 18 feet deep, so the frog climbed out of the well after 6 days.But what they overlooked is that when the frog climbed out of the wellhead, it stopped sliding down.

Therefore, the correct answer is that the frog only needs 5 days to climb out of the wellhead.In the first 4 days, the frog climbed up 12 feet. On the 5th day, the frog just finished climbing the remaining 6 feet and climbed out of the wellhead.brain teaser

What are cloth and paper afraid of?
Why do you have to treat guests to dinner at a wedding?

What is the largest organ in the human body?
When is 4 minus 3 equal to 5?

What can I borrow without repaying it?
Monkey King went to the Pantao Garden to pick the flat peaches, and planned to pack the picked peaches in bags of 10 and bring them back to Huaguo Mountain, but at the end of the packing, there were only 9 left.If there are 9 points, there are 8 left; so Sun Wukong is divided into 8 points, and the result is 7 more; according to 7 points, there are 6 more; according to 6 points, there are 5 more...

So Monkey King did the math, and divided the total number of flat peaches picked by 5, leaving 4; dividing by 4, leaving 3; dividing by 3, leaving 2; dividing by 2, leaving 1.

Do you know how many flat peaches Sun Wukong picked at least?

Don't (cloth) be afraid of [-] pieces (paper) in case.

After the announcement, there was one more person in the family for dinner.

guts.audacious in the extreme.

When miscalculation.

Excuse me.

既然知道不管怎么分，总是缺一个蟠桃，那么，如果能再多一个蟠桃，这个数目就能被10、9、8、7、6、5、4、3、2、1除尽了。由此可以知道，这个数应该是2520（以上数字的最小公倍数）。所以，蟠桃数目至少为2519个。脑筋急转弯

As soon as the father found that the amount of money in the wallet was reduced by half, he insisted that it was a good thing done by his son. Why?
Xiao Zhao has been engaged in beauty work for many years, why can't he even draw eye shadow well?
Yellow-skinned people are yellow, and green-skinned people belong to which category?
As shown in the figure below, if there is the same number (one digit) in the 3 spaces, which number should it be?

If it is the wife, she will take all the money.

Engaged in car beauty.

patient.

Since the ones digits of the two numbers on the left are the same, and the ones digit on the right is 9, the result of multiplying two identical numbers with a ones digit of 9 can only be 3 or 7.

Try these two numbers separately.

93×3=279 (not equal to the target value).

97×7=679 (qualified).brain teaser

Why does Guanyin Bodhisattva sit in the middle of the golden boys and jade girls instead of sitting next to them?
How do blind people eat oranges?

There is more than enough every year, why can't the money still be saved?

The teacher said that the earthworm can still regenerate after being cut into two pieces. Xiaodong followed the teacher's advice, but the earthworm died. Why?
Old Liu slept alone, why did he wake up with deep tooth marks on his buttocks?

Linda's birthday is on the first Thursday in January.Now know that the sum of all Thursdays in January is 80.May I ask when is her birthday?
prevent them from falling in love.

Eat with your mouth.

Get fired every year.

Xiaodong cut the earthworm vertically.

Sleeping on my dentures.

two days.brain teaser

Uncle Li went shopping in a supermarket. He only had 1 yuan and 5 cents coins in his wallet, but he bought back 123 yuan. Is this true?
A chicken feather floated from the upper reaches of the Yangtze River. Where did it come from?
There is a dark and deep cave. It is said that there are rare treasures hidden in it, so a person went to explore it very curiously. Sure enough, as the legend said, there are many footprints of people who have entered the cave.However, as soon as the man saw these footprints, he immediately gave up the idea of ​​entering the cave, and hurried away.Why?
According to the law of the given number, please judge what is the last number in this sequence?
1 3 2 6 4 12 8 24？

These 1 yuan and 5 cents add up to more than 123 yuan.

on the chicken.

There are only footprints going in, but no footprints going out.

16。变化规律是加2、减1，加4、减2，加8、减4，加16、减8……

(End of this chapter)