Analysis: (1) Hypothesis:
(2) List:
workload
time
efficiency
plan
reality
(3) Equivalence relation:
2. A chemical fertilizer plant plans to produce 65,438+020 tons of chemical fertilizer within the specified date. Due to the new technology, 3 tons of chemical fertilizer is produced every day, and the actual production time 180 tons is equal to the original planned production time 120 tons. How many tons of chemical fertilizer do you plan to produce every day?
3. The time required for A to manufacture 90 parts is the same as that required for B to manufacture 120 parts. It is known that A and B manufacture 35 machine parts per hour. Find out how many parts A and B produce per hour.
Chen Ming intends to organize some students to participate in computer network training in extracurricular activities. According to the original number of students, it is estimated that * * * will go to 300 yuan. Later, because the number of students has doubled, they will enjoy preferential treatment. A * * * only needs 480 yuan, and the average cost shared by each student participating in the activity is less than that planned by 4 yuan. What is the original number?
5. Two construction teams, Party A and Party B, completed a project together. Team B did 1 day alone, and then the two teams cooperated for 2 days to complete the whole project. It is known that the time ratio between Team A and Team B is 2:3. How many days does it take for Team A and Team B to complete the project alone?
6. The municipal engineering company built a 6000-meter-long riverbank. After 30 days of emergency repair, we learned from relevant departments that the flood season will be advanced. The company decided to send more construction personnel to speed up the construction, and the work efficiency was improved by 20%. The project was completed only five days ahead of schedule. Ask the company about the actual number of days to complete the project.
7. In order to speed up the development of the western region, an autonomous region decided to build a new highway, and two engineering teams, A and B, contracted the project. If Team A goes it alone, it will be finished on schedule. If Team B goes it alone, it will take more than six months to finish. Now Team A and Team B have been working together for four months, and the rest have been done by Team B alone, just in time. How long did it take to build this highway?
As we all know, ships travel 20 kilometers per hour in still water. If it takes the same time to sail 72 kilometers downstream and 48 kilometers upstream in a river, what is the speed of the river?
Solution: Establish the equation.
9. The distance between A and B is 135km, and two cars, one big and one small, drive from A to B at the same time. The big car is 4 hours and 30 minutes behind the small car. It is known that the speed ratio of the big car and the small car is 2: 5, so find the speed of the two cars.
Solution: Establish the equation.
10, students in group a and group b went to the nursing home 4.5km away from the school to clean up. After walking for half an hour, the students in Group B started to ride bicycles. As a result, two groups of students arrived at the nursing home at the same time. If the speed of walking is the speed of cycling, what are the speeds of walking and cycling?
1 1, Xiaoming's family, Miss Wang's family and the school are on the same road. Xiaoming's home is 3 kilometers away from Teacher Wang's home, and Teacher Wang's home is 0.5 kilometers away from school. Because Xiaoming's foot is hurt, in order to get to school on time, Miss Wang rides a bike to pick him up every day. It is understood that the speed of Mr. Wang riding a bike is three times that of walking. Mr. Wang spends an extra 20 minutes walking to work every day. What is Mr. Wang's walking speed?
12, the distance between a and b is 80km. A bus goes from a to b. Two hours later, a car left from A in the same direction. The speed of a car is three times that of a bus. As a result, the bus arrived at B 40 minutes earlier than the bus, so that we could find out the speed of the two cars.
13. In order to further alleviate traffic congestion, a city decided to build a light rail from the city center to the airport. In order to finish the project three months ahead of schedule, it is necessary to improve the original work efficiency 12%. Ask how many months the project is planned to go on.
14. In the assembly workshop of an air-conditioning factory, it was originally planned to assemble 150 air conditioners in several days. In order to get the air conditioner on the market ahead of schedule, the manufacturer decided to assemble three more air conditioners every day and overfulfil the task three days ahead of schedule. The total number of air conditioners assembled is 6 more than originally planned. How many air conditioners were originally planned to be assembled every day?
15. Beijing-Tianjin intercity railway will be put into operation on August 1 day, 2008. It is estimated that the one-way direct running time of the high-speed rail between Beijing and Tianjin will be half an hour. In a trial run, the travel time of the test train from Beijing to Tianjin was 6 minutes longer than expected, and the travel time from Tianjin to Beijing was the same as expected. If the trial operation is carried out from Tianjin to Beijing, the average driving speed is 40 kilometers per hour.
16, someone is walking at a constant speed on the expressway, and a ring road bus meets him head-on every 4 minutes; Every six minutes, a car passes behind the man; How many minutes does the bus stop leave in both directions?
17, Party A and Party B start from A and B respectively at the same time, and they go in opposite directions. After A walked 8 meters, the two met for the first time, and then A continued to go to B and B continued to go to A and be right back. They met for the second time at a distance of 6 meters from B to find the distance between A and B.
Two goods with the same weight of 18 are worth 900 yuan and 1500 yuan respectively. It is known that the value per kilogram of the first commodity is less than that of the second commodity, and the value per kilogram of these two commodities is calculated separately.
19. The bus takes 480 kilometers of expressway from A to B and 600 kilometers of ordinary highway from B to A. It is also known that the average speed on the expressway is 45Km kilometers faster than that on the ordinary highway, and the time from the expressway to the second place is half that of the ordinary highway to the second place. Find the time required for the bus to travel from the expressway to the second place.
20. The distance from A to B is 15km. A rides a bike from a to b first. After 40 minutes, B rides from A and arrives at the same time. Given that the speed of B is three times that of A, find the speed of two cars.
2 1, tractor a plowed half of a piece of land in 4 days, plus tractor b, two combined plows plowed the other half in 1 day. B How many days does it take a tractor to plow the field alone?
22. The time required for A to produce 90 parts is the same as that for B to produce 120 parts. As we all know, A and B produce 35 machine parts per hour. Find out how many parts A and B produce per hour.
23. 25 yuan of Party A, the money is 20% of the sum of Party A and Party B. How much money does B have?
24. A company has 400 yuan money and a company has 150 yuan money. If Party B gives some money to Party A, at this time, the money of Party B is 65,438+00% of that of Party A, how much money should Party B give to Party A?
Our troops attacked the enemy at the bridge. When we set out, the enemy was 24 kilometers away from the bridge, and our army was 30 kilometers away from the bridge. The speed of our army's urgent March is 1.5 times that of the enemy. As a result, we arrived 48 minutes earlier than the enemy, so we asked our army to speed up.
26. It takes the same time for a ship to sail 80 kilometers downstream as it does for a ship to sail 60 kilometers upstream. Given the current speed of 3 km/h, find the ship speed in still water.
27. When a middle school travels to a place 15km away from the school, the advance team and the brigade set out at the same time, with the speed of 1.2 times that of the brigade, and arrived at the destination half an hour in advance to make preparations. What's the speed of the advance team and the brigade?
28. Some people are now processing an average of 33 more parts per day than originally planned. As we all know, the time required to process 3,300 parts now is the same as that originally planned to process 2,365,438+00 parts. How many parts are processed on average every day?
29. A certain unit of our army carries out tasks 30 kilometers away from the station. Due to the change of circumstances, the speed of the emergency March must be 1.5 times of the original plan, so as to arrive two hours earlier as required, so as to achieve the speed of the emergency March.
The buyer of a shopping mall predicted that a shirt of this season would sell well in the market, so he bought it with 80 thousand yuan. After it was put on the market, it was really in short supply. The mall spent/kloc-0.76 million to buy the second batch of this shirt, which was twice as much as the first batch, but the unit price was 4 yuan. When this shirt was sold in the mall, the price of each shirt was 58 yuan, and the last 150 pieces were 20% off.
3 1. A wholesale and retail stationery store stipulates that you can pay at the wholesale price if you buy more than 300 pencils at a time (excluding 300 pencils), and you can only pay at the retail price if you buy less than 300 pencils. Xiaoming came to the store to buy pencils. If he buys 1 pencil for every eighth grade student, he can only pay at the retail price, and needs 120 yuan. If he buys 60 pencils, he can pay at the wholesale price, and he also needs 120 yuan.
(1) What is the total number of students in this eighth grade?
(2) If the wholesale price is the same as the retail price, how many eighth-grade students are there in this school?
32, an urgent project, because B didn't arrive, had to start with A, and half finished in six hours. When B arrives, two people do it at the same time, 1 hour to finish the second half. If b can finish the second half in x hours alone, what is the equation that x should satisfy?
33. Walk a full 3000 meters. If the speed is increased by 25%, you can arrive 30 minutes earlier. What speed should you reach?
34. The students in Class A and Class B were examined for reaching the sports standards. Results There are 48 students in Class A and 45 students in Class B. The qualified rate of Class A is 5% higher than that of Class B. What is the qualified rate of Class A?
35. The price of a commodity rises per kilogram 1/3. Last time it was 15 yuan, and this time it was 30 yuan. It is known that I bought 5 kilograms more this time than last time, so I want the price this time.
Xiaoming and his classmates go to the bookstore to buy books. They first bought a popular science book with 15 yuan, and then bought a literature book with 15 yuan. The price of popular science books is half higher than that of literary books, so they bought one more literary book than popular science books. What are the prices of these popular science books and literature books?
37. The unit price ratio of raw materials A and B is 2: 3. Raw material A with a value of 2000 yuan and raw material B with a value of 1000 yuan are mixed, and the unit price is 9 yuan. Find the unit price of a ..
38. The price of a commodity is per piece 15 yuan, which can make a profit of 25%. Find the cost price of this commodity.
39. In a store, the unit price of methyl sugar per kilogram is 20 yuan, and the unit price of ethyl sugar per kilogram is 16 yuan. In order to promote sales, 10 kg of sugar B and a pack of sugar A are mixed for sale. If the unit price of mixed candy is per kilogram 17.5 yuan, then the sales volume of mixed candy is the same as that sold separately. How many kilograms is this bag of candy?
40. The distance between the two places is 360 kilometers, and the speed when you come back is 50% higher than when you went, so the time on the way back is shortened by 2 hours, and you can get the speed when you go back.
4 1, a workshop processes 1200 parts, using new technology, the work efficiency is 0.5 times of the original/kloc-0, so it takes 10 hour to process the same number of parts. How many parts are processed per hour before and after adopting the new technology?
1, two goods with the same weight are worth 900 yuan and 1500 yuan respectively. It is known that the value per kilogram of the first commodity is less than that of the second commodity, and the value per kilogram of these two commodities is calculated separately.
2. The bus takes 480 kilometers of expressway from A to B and 600 kilometers of ordinary highway from B to A. It is also known that the average speed on the expressway is 45Km kilometers faster than that on the ordinary highway, and the time from the expressway to the second place is half that of the ordinary highway to the second place. Find the time required for the bus to travel from the expressway to the second place.
3. the distance from a to b is 15km. A rides a bike from a to b first. After 40 minutes, B rides from A and arrives at the same time. Given that the speed of B is three times that of A, find the speed of two cars.
4. A tractor A plowed half of a piece of land in 4 days, and a tractor B plowed the other half in 1 day. B How many days does it take a tractor to plow the field alone?
5. The time required for A to manufacture 90 parts is the same as that required for B to manufacture 120 parts. It is known that A and B manufacture 35 machine parts per hour. Find out how many parts A and B produce per hour.
6. 25 yuan, a company, the money is 20% of the total of both parties. B how much is it?
7. A has money from 400 yuan and B has money from 150 yuan. If B gives some money to A, at this time, B's money is 10% of A's money. How much should B give A?
Our troops attacked the enemy at the bridgehead. When we set out, the enemy was 24 kilometers away from the bridgehead and our army was 30 kilometers away from the bridgehead. The speed of our army's urgent March is 1.5 times that of the enemy. As a result, we arrived 48 minutes earlier than the enemy, so we asked our army to speed up.
9. It takes the same time for a ship to sail 80km downstream and 60km upstream. Given the current speed of 3 km/h, find the ship speed in still water.
10. When a middle school travels to a place 15 kilometers away from the school, the advance team and the brigade set out at the same time, with the speed of 1.2 times that of the brigade, and arrived at the destination half an hour in advance to make preparations. What's the speed of the advance team and the brigade?
1 1, now someone processes 33 more parts per day than originally planned. As we all know, the time required to process 3,300 parts now is the same as that originally planned to process 2,365,438+00 parts. How many parts are processed on average every day?
12, a certain unit of our army went to a place 30 kilometers away from the station to perform tasks. Due to the change of circumstances, the speed of the emergency March must be 1.5 times of the original plan, so as to arrive two hours earlier as required, so as to achieve the speed of the emergency March.
13. The buyer of a shopping mall predicted that a shirt in this season would sell well in the market, so he bought it for 80 thousand yuan. After it was put on the market, it was really in short supply. The mall bought the second batch of this shirt for176,000, which is twice as much as the first batch, but the unit price is 4 yuan. When this shirt was sold in the shopping mall, there was 65438+ for each 58 yuan.
14. A wholesale and retail stationery store stipulates that you can pay at the wholesale price if you buy more than 300 pencils at a time (excluding 300 pencils), and you can only pay at the retail price if you buy less than 300 pencils. Xiaoming came to the store to buy pencils. If he buys 1 pencil for every eighth grade student, he can only pay at the retail price, and needs 120 yuan. If he buys 60 pencils, he can pay at the wholesale price, and he also needs 120 yuan.
(1) What is the total number of students in this eighth grade?
(2) If the wholesale price is the same as the retail price, how many eighth-grade students are there in this school?