The gentleman in the blue hat first found that everyone's hat was different in color. He said, "The colors of the hats worn by the three of us are just our surnames, but no one wears the same colors as their surnames." At this time, Mr. Huang also discovered this fact. He said, "Really. What a coincidence! " . Mr. Huang wears a colorful hat (), Mr. Lan wears a colorful hat () and Mr. Bai wears a colorful hat ().
Xue Fan tip: This problem is not too difficult, so you should take it seriously. I believe you can solve it!
There are some common methods of logical reasoning in primary school olympiad, which can basically solve all logical reasoning problems!
And logical reasoning is often tested in various competitions. So we must pay attention to it!
These things are generally accumulation methods!
The more difficult logical reasoning is to add some calculations. It takes rigorous reasoning to get the result!
This requires the assistance of other knowledge.
It is generally recommended that children in grades one and two can deal with very simple problems of right and wrong.
The third grade can deal with simple analytical problems.
The fourth and fifth grades will add some logical reasoning questions on other topics!
If you want to do logical reasoning, you need to accumulate some common sense of life. All these things should be accumulated in the first and second grades, so you don't need to study Olympiad in the first and second grades, as long as you master the life knowledge you can master, you will become an Olympiad master in the future!
Two problems of happy training:
A broken car has to walk two miles, one mile up the hill and one mile down the hill. When it goes uphill, the average speed is 15 miles per hour. How fast can you go down the hill in the second mile? 30 miles per hour? Is it 45 miles? )
B. Amebic protozoa reproduce by simple division, each division takes 3 minutes. Put an amoeba into a container filled with nutritious ginseng liquid. 1 hour later, the container is full of amoebas. If you start with two amoebas instead of one, how long will it take to fill the container?
About half an hour, I guess? )
The answer in brackets is the questioner's answer, which may be wrong. Please do it yourself. It's best to write out the formula and process, only write the answer without commenting!
After the heavy snow in primary school, the teacher found that the snow at the school gate had been swept clean and asked the four students present who swept it: A said it wasn't me; B said it was d scan; C said it was B-ultrasound; D said b was lying. Ask who told the truth. Who swept it when it snowed?
Answer: If only 1 people tell lies, everything else is true.
B says it's D, D says B is lying, and someone must be lying.
If D lied, then D swept away and C lied, which is beside the point.
So B, B lied and ACD told the truth.
The Fifth Grade Olympiad in Primary School: Thematic Training (Logical Reasoning)
Logical reasoning means that in some problems, there are no numbers and figures or figures in conditions and conclusions, so it is neither an arithmetic problem nor a geometric problem. There is also such a problem, which seems to be an arithmetic or geometric problem on the surface, but seldom uses arithmetic or geometric knowledge in the process of solving it. To solve all these problems, we need to deeply understand the conditions and conclusions, analyze the key points and find the breakthrough.
Special Training of Logical Reasoning in Fifth Grade Olympic Mathematics;
1. Among the three boxes, one contains two black balls, one contains two white balls, and one contains one black ball and one white ball. Now the labels on the three boxes are all wrong. Can you take a ball out of one box and make sure what balls are in the three boxes?
Four students, A, B, C and D, all have different numbers printed on their jerseys. Zhao said, "A is number two, and B is number three." Qian said, "C is number four, and B is number two." Sun said, "Ding is number two and C is number three." Li said, "Ding is number one, and B is number three."
3. In a school math contest, eight students, A, B, C, D, E, F, G and H, won the top eight. The teacher asked them to guess who was the first. A said, "Either F comes first or H comes first." B said, "I am the first." C said, "G comes first." D.
4. A visiting group chooses a place to visit from five places: A, B, C, D and E according to the following conditions: ① going to A and B; ② Go to at most one of B and C; ③ Go to at least one of D and E; 4 go to C and D at the same time or not; ⑤ If you want to go to E, you must go to A and D. Where will the delegation go?
There are 12 people in the room. Some people always tell lies, while others tell the truth. One of them said, "There are no honest people here." The second said, "There is at most one honest man here." The third said, "There are at most two honest people here." By analogy, the twelfth said, "There are 65433 here at most."
6. Party A, Party B, Party C and Party D agreed to meet at the gate of the park on 10 in the morning. After meeting, Party A said, "I will arrive six minutes early, and Party B will arrive on time."
B said, "I am four minutes ahead and C is two minutes behind." C said, "I'm three minutes early and D is two minutes early." D said, "I thought I was late 1 minute. In fact, it was not until the last 1 minute that I heard the announcement of Beijing time 10 on the radio. "
According to the above conversation, which of the four people has the fastest watch and how many minutes faster?
7. Four students, A, B, C and D, are in the same classroom. One of them is doing a math problem, one is reading English, one is reading a novel and the other is writing a letter. As we all know:
① A is not learning English or reading novels;
② If A is not doing math problems, then D is not learning English;
Some people say that B is doing math problems or learning English, but this is not the case.
(4) If Ding is not doing a math problem, then he must be reading a novel, which is wrong;
C neither reads novels nor learns English.
Then who is writing a letter?
At the banquet table of the International Hotel, four friends, A, B, C and D, had an interesting conversation. They used Chinese, English, French and Japanese respectively, and they also knew:
① Party A, Party B and Party C can speak two languages, while Party D can only speak one language;
There is a language that three out of four people can speak;
③ A can speak Japanese, D can't speak Japanese and B can't speak English;
④ A and C, C and D cannot talk directly, but B and C can talk directly;
No one knows both Japanese and French.
Please judge what language they can speak according to the above situation.
9. Three students, A, B and C, wearing three different colors of hats and clothes, took part in an activity to host the Olympic Games. As we all know:
The colors of hats and clothes are only red, yellow and blue;
② A didn't wear a red hat and B didn't wear a yellow hat;
(3) The students wearing red hats don't wear blue clothes;
(4) Students wearing yellow hats wear red clothes;
B is not wearing yellow clothes.
What colors of hats and clothes do A, B and C wear?
10.5 Students A, B, C, D and E took part in a competition. Someone predicted the results of the game in the order of ABCDE, and the results did not guess any ranking, nor did they guess any pair of adjacent rankings (that is, two people actually ranked adjacent, but in this person's guess, the rankings were also adjacent and in the same order); Another person predicted that the result of the competition would be DAECB. He guessed two places correctly and two pairs of adjacent places correctly. Find out the result of this competition.