Answer: The 9 yuan money spent by each person already includes the 2 yuan money hidden by the waiter (that is, the preferential price 25 yuan+the waiter owns 2 yuan =27 yuan =3*9 yuan). Therefore, when calculating the composition of 30 yuan, you should not count the 2 yuan money hidden by the waiter, but add 1 yuan returned to everyone. Namely: 3*9+3* 1=30 yuan is just right! You can also think about it from another angle .. Those three people went out of 30 yuan and spent 25 yuan, and the waiter hid 2 yuan, so each person spent 9 yuan, plus the share of 1 yuan, which happened to be 30 yuan. So this dollar was found. Summary: This puzzle is mainly because it separates 2 yuan money from 27 yuan money. The original algorithm mistakenly thought that the 2 yuan left by the waiter privately was not included in the 27 yuan, so the wrong result was 1 yuan. In fact, this 27 yuan includes 2 yuan money left by private individuals, plus the returned 3 yuan money, and the result happens to be 30 yuan.
2. A person went to buy onions and asked how much they cost per catty. Onion sellers say it's 1 yuan, 1 Jin, which is 100 yuan. The onion buyer asked the onion seller to separate from the onion seller, saying that all the onion sellers bought them, weighing 50 kg of onions, 50 kg of onions, and 50 kg of onions. 7 equals the lush green of 35 yuan 50*3 equals 15 yuan 35+ 15 equals that the onion buyer in 50 yuan gave the onion seller 50 yuan and left, but the onion seller was puzzled why it was 100 yuan, and why 50 yuan bought it? Why do you think this is?
Answer: 1 yuan a catty, indicating that onions and vegetables are one yuan a catty. When he bought it separately, the green onions cost 73 cents. In fact, their weight has not changed, but the unit price has changed. Green onions are less than 3 cents per catty, green onions are less than 7 cents per catty, and I bought them for 50 yuan at last.
There is a well with a depth of 7 meters. A snail climbs up from the bottom of the well, climbing 3 meters during the day and dropping 2 meters at night. How many days can a snail climb out of the well? Answer: 5 days. Many people say that this problem is seven days without thinking ... In fact, in a very simple way .. you draw a piece of paper and it comes out ... This problem is very simple. ...
4. 1 yuan How many peaches can a peach eat? Answer: 1 yuan buys 10, and there is still 10 left after eating. Change three more peaches and eat the remaining four stones. Change 1 peach, and there are 2 stones left after eating. There are/kloc-0 peaches on credit, and there are still 3 stones left after eating. Give all the cores to the peach seller and the credit. So, you ate10+3+1+1=15 peaches. This is a well-known method ... there is another way ... don't buy ten at a time ... individually ... three for the first time ... two for the second time ... and two for the third time ... so ... it is very simple ... and it is 15.
There are twelve ping-pong balls of the same shape and size, only one of which is different in weight from the other eleven. Now it is required to weigh the ball three times with an unweighed scale to find out whether it is heavier or lighter than the other eleven balls. A: They are divided into A B C 3 groups, with 4 capsules in each group. For the first time, there may be three results .. A>B or A=B or A.
6. A businessman rode a donkey across the desert of 1000 km to sell 3000 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: 534. First, camel 1000 radish goes forward x 1 km, puts down 1000-2*x 1 radish, and then takes back the rest x 1 radish; Then camel 1000 radish, take x 1 radish at x 1 km, and let donkey camel 1000 radish; Continue to move forward to the distance of x2 km from the starting point, put down 1000-2*(x2-x 1) radish and return to the starting point after eating radish at x 1 km; Finally, the camel took a thousand radishes and walked to x 1, and x2 took all radishes in turn, and then walked to the end. The remaining radishes at x 1 and x2 are less than or equal to x 1 and (x2-x 1) respectively. Under the constraint of this inequality, it is enough to find the maximum of two remaining radishes, because in fact, the number of two remaining radishes is the number of radishes that can finally reach the end point. Finally, x 1=200, x2= 1600/3. The total distance traveled by the donkey is 2 * x1+2 * x2+1000 = 2466+2/3, which means that only one radish can be eaten after walking one kilometer, that is, the total number of carrots eaten is rounded to 2466, so the last radish that can be sold is 3000-2466=534.
7. It is said that one day a pirate ship was hit by a cow that fell from the world, and five unlucky guys had to flee to an isolated island and found the island very lonely. Fortunately, there is a coconut tree and a monkey! Everyone picked all the coconuts and put them together, but it was late, so they went to bed first. At night, a guy got up quietly and divided the 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 in their original places, and finally quietly went back to sleep. After a while, another guy got up quietly. Quietly divide the remaining coconuts into five parts. One coconut was given to the lucky monkey, and then one was dropped quietly. The remaining coconuts were mixed together and put back in their original place, and finally fell back to sleep quietly. Soon ... soon ... 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?
Answer: There are at least 1562 1 coconuts in this pile. The first person gave 1 monkey, 3 124 was hidden, leaving 12496. 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.
8. There is a treasure on an island. You see three islanders, big, medium and small. You know the big islander knows whether the treasure is on the mountain or under the mountain, but sometimes he tells the truth and sometimes he lies. 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 use their left or right hands to indicate whether 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? Tip: If you ask an islander where the treasure is, he will ask how you know where it is. Answer: For convenience, we write large, medium and small islanders as ABC (actually, we don't use C). The first question is A: Is the treasure on the mountain? The second question is B: Is A correct? The third question is B: 1+ 1 = 2, right? Ok, now the first question is, we don't know whether A answered "yes" or "no" or whether A answered "yes" or "no". We only know whether A raised his hand with his left or right hand, so we leave him alone. Look at the second question. No matter whether A's answer is "yes" or "no", as long as A's answer is correct, B will answer correctly in the second question, so he should answer "yes" (if he can speak Chinese). Still the same. No matter whether A's answer is "yes" or "no", as long as A's answer is wrong, B will also answer wrong in the second question. So anyway, B's raised hand means "yes"; The third question: since we know what the right hand means, we can determine whether A is true or false as long as we know whether B's answer just now is true or false, because the truth of both must be the same. So just ask a question, like 1+ 1=2, right? There is another way: First, ask a random person: Are you telling the truth? That person will definitely raise his hand for yes, because if he is telling the truth, he will raise his hand for yes, and if he is lying, he will also raise his hand for yes, so it can be concluded that the hand represents yes and then ask the China islanders: Did the big islanders say that the treasure is on the mountain? China islanders must have answered correctly, which means the treasure is where China islanders said.
Because if the China islanders say, if the big islanders are telling the truth, then the China islanders are telling the truth, then the treasure must be on the mountain. If the big islanders are telling lies, then the China islanders are telling lies. In fact, the big islanders mean that the treasure is under the mountain, but because it is fake, the treasure is still on 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? Answer: 25 19 people. As long as it is 315× (11x+8)-1,because 9 is three times that of 3, so 3 doesn't count. According to the topic, the law is 5,7. If the multiple of 9 is less than 1, then divide by the multiple of 5×7×9 = 3 1 1, and the period is 731062951840 * */kloc. Because it is divided by 1 1, there is a simple algorithm that does not need to be tried one by one. Because 3 15- 1 is divisible by 1 1, we take the periodic remainder of 1.
10. Some people want to buy some set dishes. 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? Answer: You can buy 12 set tableware. The price of spoon and fork is 1/2 1, and the price of knife is 1/28 ... a set of total price1/21+65438+28 =1/kloc-0. ..
So you can buy 12 sets ... all the money is used up.
1 1. The police found a thief and went after him. The thief ran and ran. A river appeared in front of him, with a width of 12 meters. Beside the thief and the police, there is a tree 12 meters high. All the leaves on the tree are gone. The thief was surrounded by a collar and asked how to cross the river. Answer: Tie the collar to the top of the tree, and the thief will swing with the collar. Let go when the collar and trunk make a 45-degree angle, and the thief will be thrown across the river. In addition, I also referred to other people's answers. Some people say that according to the title, it was winter ... so ... the water froze ... and ran over. ...