2. It takes Party A and Party B 6 days to complete a project, and Party B and Party C need 10 days ... Now Party A, Party B and Party C have cooperated for 3 days, and Party B has just finished the remaining 6 days. How many days does it take to complete this project alone?
3. It takes Party A 6 minutes, Party B 5 minutes and Party C 4.5 minutes to manufacture a part. At present, there are 1590 parts, which are assigned to three of them and are required to be completed at the same time. How much is each of Party A, Party B and Party C?
An airplane can fly for 6 hours with fuel. Fly with the wind when flying out, with an hourly speed of 1500 km, and fly against the wind when flying back, with an hourly speed of 1200 km. How many kilometers should this plane fly back?
5. 3/ 10 of the students in Class A is equal to 2/5 of the students in Class B. There are 105 students in Class II. How many students are there in Class A and Class B respectively?
6. The master and the apprentice processed 84 parts, and the number of parts processed by the apprentice was 1/5, which was 3 less than the master's 1/4. How many parts did the master and the apprentice each process?
7. Ada Garden Primary School has students serving the community, and the number of boys is two-thirds of that of girls. Later, three boys attended and three girls had something to leave. At this time, the number of boys is 3/4 of that of girls. How many men and women have participated in community service?
8. Newly purchased rice and flour 100 kg in the canteen. It is known that 1/3 of rice is 9 kilograms more than 3/ 10 of flour. How many kilograms of rice and flour are there respectively?
9. Three fifths of the students in primary schools are girls. In the new semester, the school transferred 258 students, and the number of girls increased by 1/3, while the number of boys just doubled. How many students were there in the original school?
10. I bought a batch of fruits in the store, which was sold by 30% on the first day and 150kg on the second day, 20% more than the first day. How many kilograms are there in this batch of fruit?
1 1, Party A and Party B walked through two places at the same time and met 40 meters away from the midpoint. It is known that Party A walked 55% of the whole journey. A How many kilometers did you travel?
12. After deducting 1000 yuan from her salary in August last year, Xiaoming's mother paid personal income tax at the rate of 5% 15 yuan. How much did Xiaoming's mother earn last August?
13, the cargo capacity of ship A is 25% more than that of ship B, and the cargo capacity of both ships A and B is 3,600 tons. How many tons are each loaded by Ship A and Ship B?
14. Dr. Zhang needs 75% alcohol to see a doctor. Now there is 95% alcohol 18 kg. How many kilograms of water do you need?
15, one side of a square is reduced by 20%, and the other side is increased by 2 meters to get a rectangle, and the area of this rectangle is equal to that of the original square. How many square meters was the original square?
16, there are 79 students in Class A and Class B. The number of girls in Class A is 60% of that of boys, and the ratio of boys to girls in Class B is 6: 7. How many boys are there in Class A?
17. The rice stored in the grain depot is 7/8 of the flour. After 20% of the rice is transported away, the stored flour is more than rice 120 tons. How many tons of rice and flour were originally stored in the grain depot? [elf children's website]
18, there are two pieces of cloth, one is 40m long and the other is 30m long. After using two pieces of cloth with the same length, it is found that the remaining length of short cloth is 3/5 of that of long cloth. How many meters does each piece of cloth use?
19. The number of books in bookshelf A is 4/7 of that in bookshelf B. After adding two bookshelves 154, the number of books in bookshelf A is 5/6 of that in bookshelf B. How many books are there in bookshelves A and B?
20. In the extracurricular activity group of "Exploring Nature", boys accounted for 5/9 last semester, but after adding 2 1 girl this semester, boys only accounted for 2/5. How many girls are there in this group now?
2 1, Li Shifu processed a batch of parts, and the unqualified parts were119 of qualified parts. Later, after careful selection, two unqualified products were found from the qualified products. At this time, the qualified rate of products is 94%. How many qualified products are there?
22, a batch of parts, Party A and Party B cooperate to complete in 20 days, Party A makes three more than Party B every day, and Party B has five days off, so when it is finished, Party B only makes half of Party A's .. How many parts are there in this batch?
23. The store promotes a commodity and sells it at 65% of the original price. It is known that the current price is lower than the original price, 350 yuan. What's the current price?
24. A brine is made of salt and water in a ratio of 2: 25, with a weight of 2 16g. How many grams of salt is added to make the ratio of salt to water 1: 5?
25. It takes 20 days for Party A to do a job alone, and 30 days for Party B to do a job alone. Now that Party A and Party B are cooperating, Party A went on a business trip for several days, which took 15 days to complete. How many days did Party A go on a business trip?
26. A manuscript was originally planned to be copied in five days and then in four days. What percentage has the work efficiency been improved?
27. When the base of the triangle increases by 10% and the height decreases by 10%, what percentage is the area of the triangle now?
28. Two cars A and B are heading for B at the same time. When car A is halfway through, car B is 54 kilometers away from car B. When car A arrives at car B, car B has already traveled 80%. How many kilometers is AB?
29. I hope primary school can buy 50 footballs, and there are three stores to choose from. The football prices of the three stores are all within 25 yuan, but the discount methods of each store are different. Shop A: If you buy 10 soccer balls, you will get two for free. If you buy less than 10, you won't get them. B: 5 yuan is given a discount for each football. Store C: The purchase price reaches 100 yuan, and it is returned to 20 yuan. In order to save money, which store should Hope Primary School buy?
30. Lao Zhang has a house worth 400 thousand. Because of the urgent need for cash, I sold it to Lao Li at a 10% discount. After a while, the house price rose by 10%, and Lao Zhang wanted to buy the house back from Lao Li. Think about it, if Lao Zhang buys back the house, how many ten thousand yuan will he lose?