Elementary school 6th grade Olympiad hundreds of points application questions, difficult, difficult,

The two water pipes of A and B are opened separately and filled with a pool of water, which takes 20 hours and 16 hours respectively. If the pool is empty, open the two water pipes A and B at the same time, and after 5 hours, open the drainage pipe C, and ask how many hours it will take for the pool to be full? Solution:

I'm autonomous, I'm happy, I'm innovative.

The ratio of boys to girls in a certain elementary school is 16:13, and then several girls are transferred to this school, and the ratio of boys to girls becomes 6:5, and there are 880 students in this school, how many girls are transferred?

42 students in a class participated in tree planting, the average number of male students planted 3 trees, the average number of female students planted 2 trees, it is known that there are 56 more male trees than female students, how many male and female students are there?

1. Legend has it that there are some treasures in the cave, and it takes 10 hours to carry the treasures of a cave, 10 hours for the blue cat, 12 hours for naughty, and 15 hours for Fei Fei, there are the same caves A and B, the blue cat is in cave A, and Naughty starts to carry treasures at the same time in cave B, Fei Fei begins to help the blue cat move, and goes to help Naughty move halfway, and finally finishes moving the treasures of the two caves at the same time, ask: Fei Fei helped the blue cat carry for a few hours?

2. Increase the length of a rectangle by 5dm and the width by 8dm to obtain a square with an area of 181 square decimeters more than the original rectangle, what is the side length of the square?

3. The fast, medium and slow three cars at the same time from the same place along the same road to chase a cyclist, the three cars took 6 minutes, 10 minutes, and 12 minutes respectively to catch up with the cyclist, it is known that the fast car travels 24 kilometers per hour, the slow car travels 19 kilometers per hour, how many kilometers does the car travel per hour?

There are 1 yuan coins and 5 jiao coins, and there are several jiao coins, which are worth a total of 675 jiao. If you swap the 1 yuan coin and the 5 jiao coin, there will be a total of 600 jiao. How many 5 dimes are there?

Elementary school

1.The time the fox runs 5 steps is 3 steps away from the dog and the distance the dog runs 4 steps and the fox runs 7 steps. Now that the fox has run 30 meters, the dog starts chasing it, asking how many meters the dog can run to catch the fox? The answer is 630 meters.

2.Someone travels from home to work, 1 3 miles by bicycle and 2 3 miles by car; When he returned home from work, he rode a bicycle for the first 3 8 hours and took a bicycle for 5 8 hours, and as a result, the time to go to the unit was more than the time it took to go home, and it is known that he rode a bicycle for 8 kilometers per hour and traveled 16 kilometers per hour by car, so how many kilometers did the person travel from home to the unit? The answer is 78 km (there may be many people who calculate 96 km, but it is absolutely wrong).

1. Divide a number by 3 and balance 2, divide by 5 and balance 3, divide by 7 and balance 2, find the minimum number suitable for this condition?

2. After the mathematics competition, Xiao Ming, Xiao Hua and Xiao Qiang each won a medal, one of them won the gold medal, one won the silver medal, and one won the bronze medal. Teacher Wang guessed:"Xiao Ming won the gold medal; Xiaohua shall not be golden; Xiaoqiang is not allowed to have a bronze medal.

As a result, Mr. Wang only guessed one correctly. Then Xiao Ming gets the card, Xiao Hua gets the card, and Xiao Qiang gets the card.

3. There are 1987 beads around the circumference, and each bead is dyed twice, or twice all red, or twice all blue, or once red, once blue. In the end, there were 1,987 dyes of red and 1,987 times of blue dyeing. At least one bead was verified to have been dyed red or blue.

1 The mother is 28 years older than her son this year, and in 4 years the mother is 5 times older than her son. How old is my son this year?

See for yourself the rest.

1.Divide by 3 and divide by 7 are all 2, then we find the least common multiple of 3 and 7 is 21, and the remaining 2 is added 2 21 + 2 = 23 We are checking that 23 divided by 5 is just the remainder of 3, so the minimum number suitable for this condition is 23

2.Xiao Ming won the bronze medal, Xiao Hua won the gold medal, and Xiao Qiang won the silver medal.

3.Prove it yourself.

There are two ships of A and B with the same amount of goods on the wharf, and one of the ships of goods is unloaded separately, A takes 12 hours, B takes 15 hours, and C takes 20 hours, and now A is on ship A, B is on ship B, and starts unloading at the same time, C first helps A, and then helps B, and as a result, the goods of the two ships are unloaded at the same time, and how many hours does it take for C to help A unload?

The mother is 40 years old and the son is 8 years old this year.

1. A class has a meeting, the number of people who ask for leave is 1 9 of the number of attendees, and another person asks for leave to leave in the middle, so that the number of people who ask for leave is 3 22 of the number of attendees, so how many people are there in this class?

The total number of students decreases by 1 person, 9 5 = 45, 22 2 = 44, 45 44 = 1, so there are 45 students in this class.

2. There are 260 students in the second grade of a primary school, of which boys account for 8 13 of the total number of students in the whole grade, in order to make girls at least 3 7 of the total number, so it is decided to recruit some more girls, so how many girls will be recruited at least?

260 8 13 (1 3 7) 260 = 20 (person).

3. The canteen bought three kinds of vegetables: radish, green vegetables and potatoes. The weight of radish accounts for 2 5 of the weight of the three types of vegetables, the weight of green vegetables is 1 4 of that of potatoes, radish is 360 kg less than potato, how many kg of radish is bought in the canteen?

Turnips account for all: 2 5

Potatoes account for the total: (1 2 5) 4 (1 4) = 12 25

Turnips are: 360 (12 25 2 5) 2 5 = 1800 (kg).

4. A, B, C, and D planted a total of 60 trees, the number of trees planted by A is 1 2 of the other three, the number of trees planted by B is 1 3 of the other three, and the number of trees planted by C is 1 4 of the other three.

As can be seen from the known conditions:

The number of trees planted by A is 1 3 of all, the number of trees planted by B is 1 4 of all, and the number of trees planted by C is 1 5 of all.

Ding planting trees is: 60 (1-1 3-1 4-1 5) = 13 (trees).

5. Football match tickets are 15 yuan a ticket, and after the price reduction, the audience has increased by half, and the income has increased by 1 5, how much is the price reduction of a ticket?

Assuming that there were 2 people, the ticket revenue was 15 2 = 30 (yuan).

Now there are 2 people), the ticket income is 30 (1 + 1 5) = 36 (yuan), and the average ticket is 36 3 = 12 (yuan).

The price of one ticket has been reduced: 15 12 = 3 (yuan).