1) three people went to live,

One night in 30 yuan.

Three people each paid 10 to make up 30 yuan and gave it to the boss.

Later, the boss said that it was enough to give 25 yuan a discount today.

Take out 5 yuan and ask the waiter to return it to them.

The waiter secretly hid 2 yuan,

Then,

Divide the remaining 3 yuan money among three people,

Everyone gets 1 yuan.

In this way,

Everyone handed in 10 yuan.

Now it's back to 1 yuan,

Namely 10- 1=9,

Everyone only spent 9 yuan's money,

Three people each, 9 yuan,

3×9 = 27 yuan+2 yuan hidden by the waiter =29 yuan,

Where's the other dollar?

This question caused a great response in an interview in New Zealand.

Who knows the answer?

(1) The waiter's 2 yuan is in 27 yuan. Everyone takes out 9 yuan, the boss takes 25 yuan, and the waiter takes 2 yuan.

A man went to buy onions.

How much is a catty of onions?

The onion seller said 1 yuan 1 kg, which means 100 kg, and it costs 100 yuan.

The onion buyer asked if the onion was sold separately from the onion.

The onion seller said that what he sold was 7 hairs and 3 hairs and green.

All the onion buyers bought it.

Weigh 50 kg of green onions and 50 kg of green onions.

The final calculation is that 50*7 equals 35 yuan.

50*3 equals 15 yuan.

35+ 15 equals 50 yuan.

The onion buyer gave it to the onion seller, leaving 50 yuan.

But the onion seller is confused.

Why do onions cost 100 yuan?

And why do you buy onions for 50 yuan?

Why do you think this is?

Think about it and leave the answer.

(2) Because no matter how green it is, it costs a dollar. Even if they are sold separately, they are still one yuan a catty.

(3) There is a well 7 meters deep.

A snail climbed up from the bottom of the well.

Climb 3 meters during the day and drop 2 meters at night.

How many days does it take for a snail to climb out of the well?

(3) The correct answer is 5 days. I climbed 1 m on the first night, 2m on the second night, 3m on the third night, 4m from the wellhead, 4m on the fourth night and 3m from the wellhead, and I can climb to the mouth of the cave during the day on the fifth day. There is still time at night, so I should be able to climb out of the well.

(4). A peach with ten cents.

Three peaches for one peach.

1 yuan How many peaches can you eat?

Leave a message when you think about it, and write down the way you eat peaches ~

14. Buy 10 peaches first, eat the remaining 10 peaches, and then exchange 9 peaches for 3 peaches, with 1 peach on hand; After eating three peaches, you can change 1 peach. After eating, there are only two peaches left in your hand, so you can't change peaches. 10+3+ 1= 14 peaches and 2 peaches.

(5) There are twelve ping-pong balls with the same shape and size, and only one of them is different in weight from the other eleven. Now it is required to weigh the ball three times with an unweighed scale, find out the ball with abnormal weight and know whether it is heavier or lighter than the other eleven balls.

Divide the 12 ball into three groups,

Group number: a: 1234b: 5678c: 9, 10,1,12. Set a different ball to x.

The first AvsB (that is, group a and group b are called)

1. If the weights are equal, the X ball is in Group C. Then take 123vs9, 10, 1 1.

(1) If the weights are equal, the X ball is 12. Then take 1vs 12 to know the weight of the ball 12.

(2)123 > 9,10,11. When the weights are not equal, X is on the light side and is a light ball. When the weight is equal, the X ball is 1 1, which is light.

(3) 123 & lt； 9, 10, 1 1. Similarly, 9vs 10, when the weights are not equal, X is on the heavy side and is a heavy ball. When the weights are equal, the X ball is 1 1, which is a heavy ball.

2. A>b and Qu 123456789 were divided into three groups,123,456,789.

The second name is 456vs789.

When 456=789, then X is in the ball 123, and it is a heavy ball. Then take 1vs2, the one that is biased is the X ball, and the other is the heavy ball.

456 > In 789, it may be 4 or 78 balls, if 4 is a heavy ball, if 78 is a light ball. Take 7vs8 again, if the weight is equal, it is the No.4 ball, and the ball is heavy; If the weights are not equal, the light ball is the X ball, which is light.

456 & lt789, the X ball is at 56 balls, and it is a light ball. According to 5vs6, the light ball is the X ball, which is a light ball.

3, A<b, three groups with 2 points. 123,456,789。

456vs789

When 456=789, the X ball is in the ball 123, which is a light ball, and then take 1vs2. When the weight is equal, the X ball is No.3, and when the weight is not equal, the X ball is on the light side and is a light ball.

456 >789, the X ball is on the 56th ball, which is a heavy ball, and then it is called 5vs6, and the X ball is on the heavy side, which is a heavy ball.

456 & lt789, X is on the 4th, 7th and 8th, if the 4th is a light ball, if the 7th and 8th are heavy balls. Take 7vs8 again, the weight is equal to No.4, and the weight is not equal to X, which means the ball is heavy and biased.

(6) A businessman riding a donkey has to cross the desert of 1000 km to sell 3,000 carrots. It is known that donkeys can carry 1000 carrots at a time, but eat 1 carrot every 1 km. Q: How many carrots can a businessman sell at most?

Answer: It can sell for 3000 yuan at most. This is a brain teaser: first, merchants sell on donkeys, not carrots. It is possible that carrots have been sent away first through other channels; Secondly, he may not cross the desert to 1 km, because he only said that the desert is 1 1,000 km long, but didn't say how wide it is, so he shouldn't go that far to cross the desert at all, otherwise he would ride a camel instead of a donkey.

It is said that one day the pirate ship was hit by a cow that fell from the world, and five unlucky guys had to flee to an isolated island and find it alone. Fortunately, there is a coconut tree and a monkey! Everyone picked all the coconuts and put them together, but it was late, so we went to bed first.

A guy got up quietly at night, quietly divided the coconut into five parts, found that there was an extra coconut, so he gave it to the lucky monkey, then quietly hid one part, then mixed the remaining coconuts together and put them back in place, and finally quietly fell back to sleep.

After a while, another guy quietly got up and quietly divided the remaining coconut into five parts. As a result, he found an extra coconut and gave it to the lucky monkey. Then he quietly hid a part, mixed the remaining coconuts together and put them back. Finally, he quietly dripped back to sleep.

After a while. ......

After a while. ...

In short, all five people stood up and did the same thing. Everyone gets up in the morning and shares coconuts with ulterior motives. This monkey is really unlucky, because after dividing the coconut into five points this time, there is another coconut, so we have to give it again. The question is, how many coconuts are there in this pile?

(This pile of coconuts is at least 1562 1.

The first man gave 1 monkey, hid 3 124 monkeys and left 12496 monkeys.

The second man gave 1 monkey, hid 2499 monkeys, and left 9996 monkeys.

The third person gave 1 monkey and hid 1999 monkeys, leaving 7996 monkeys.

The fourth person gave 1 monkey and hid 1599 monkeys, leaving 6396 monkeys.

The fifth person gave 1 monkey, hid 1279 monkeys, and left 5 1 16 monkeys.

Finally, everyone divided it into five parts, each 1023, and the extra 1 was given to the monkey.

There is a treasure on an island. When I saw three islanders, I knew that the big islander knew whether the treasure was on the mountain or under the mountain, but sometimes he told the truth and sometimes he lied. Only Nakajima people know whether Oshima people are telling the truth or lying, but Nakajima people themselves tell the truth when the previous person tells the truth and tell lies when the previous person tells lies. Two islanders raise their left or right hands to indicate whether they are right or not, but you don't know which hand indicates yes and which hand indicatesno. But he always tells the truth or lies, and you don't know which of these two types he is. Can you ask whether the treasure is on the mountain or under the mountain with the least number of questions?

(Just three questions:

The first question for the big islanders: Is the treasure on the mountain?

The second question for China islanders: Are the big islanders telling the truth?

The third question for islanders: Does the left hand mean yes?

The first question, if the big islanders tell the truth and raise their left hand, then the second question, the middle islanders also raise their left hand, and the third question, the small islanders will say yes; Then the treasure is on the mountain;

The second question, if the big islanders tell the truth and raise their right hands, then the second question, the middle islanders also raise their right hands, and the third question, the small islanders will say yes, then the treasure is on the mountain;

The first question, if the big islanders tell lies and raise their left hand, then the second question, the middle islanders also raise their left hand, and the third question, the small islanders will say no, then the treasure is at the foot of the mountain;

The first question, if the big islanders tell lies and raise their right hands, then the second question, the middle islanders also raise their right hands, and the third question, the small islanders will say no, then the treasure is at the foot of the mountain.

(9) How many tables and people are there in a room?

If there are three people at a table, there are two more.

If there are five people at a table, there are four more.

If there are seven people at a table, there are six more.

If there are nine people at a table, there will be eight more.

If 1 1 one table for each person, that would be just right.

How many people are there in this room?

According to the meaning of the question, three people are missing a table, five people are missing a table, seven people are missing a table, and nine people are missing a table; Then their least common multiple is one less, and the least common multiple of 3, 5, 7 and 9 =5*7*9=3 15, then n times of 3 15 is less1; Knowing that 1 1 happens to be a multiple of 1 1, there is: 315m-1=1n; n =(3 15M- 1)/ 1 1 .

M and n are both positive integers. When M=8, there are n = (315 * 8-1)11= 229 satisfying conditions (if m is less than 8, there are no satisfying conditions). So the total number of people is:11n =11* 229 = 2519. The total number of tables is at least: 25 19/3=839.66, which means at least 840 tables.

(10) Someone wants to buy some tableware. After going to the tableware shop, they found that they could buy 2/kloc-0 forks and 2/kloc-0 spoons or 28 knives with their money. If the number of forks, spoons and knives he bought is not uniform, he can't match the whole set, so he must buy the same number of forks, spoons and knives, just to run out of money. What would you do if you were this person?

Let the total money be 1, then the money for a spoon and fork is 1/2 1, and the money for a knife is 1/28.

The total price of a set of knives, forks and spoons is1/21+1/28 =112.

So the money for buying 12 sets is exactly 1. Only in this way can all the money be used up.

The police found a thief.

The police chased the thief and the thief ran away.

Running and running, there is a river ahead.

This river is 12 meters wide, and there is a tree on the thief and policeman side of the river.

The height of the tree is 12 meters, and all the leaves on the tree are gone.

The thief was wearing a 6-meter-long collar.

Ask the thief how to run across the river

(1 1) Tie the scarf to the top of the tree and the thief will swing with it. When the scarf makes a 45-degree angle with the trunk, throw the thief across the river. Unfortunately, however, the thief will lose a collar, and even more unfortunately, the police can swing like this to continue the chase. .............