1. Xiao Wang and Xiao Li live on the first floor. They work from home. Xiao Wang walked for 20 minutes before Xiao Li left. Given that Xiao Li's speed is three times that of Xiao Wang, how long will it take Xiao Li to catch up with Xiao Wang after starting?
2. A walks 80 meters per minute and B walks 50 meters per minute. In the afternoon 1: 30, they walked back in the same place for 6 minutes. A turned around and caught up with B. When did A catch up with B?
A school organized students to go to the Great Wall for a spring outing and rented a bus. The distance from the school to the Great Wall is150km. The bus and a school bus leave from school at the same time. When the bus arrived at the Great Wall, the bus was still 30 kilometers away. Given a bus speed of 60 kilometers per hour, how many kilometers is the bus faster than the bus?
4. Party A and Party B start from two opposite vertices of a square pool with a circumference of 800 meters and walk counterclockwise at the same time, with Party B in the front and Party A in the back. A walks 50 meters per minute, and B walks 46 meters per minute. How long does it take for A and B to leave at the same point?
5. Party A and Party B set out from East Village to West Village at the same time. Party A's speed is 6 kilometers per hour, while Party B's speed is 4 kilometers per hour. Party A rested for 2 hours, and the result was later than Party B 1 hour. What is the distance between the two villages?
2. Choose the second part of the third year Olympic math problem.
1.Students from Class A and Class B took part in the activity of "Greening the Motherland". It is known that Class B plants 2 more trees per hour than Class A, and the time for Class A to plant 60 trees is equal to that for Class B to plant 66 trees. How many trees do Class A and Class B plant per hour?
In order to alleviate the traffic jam, 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, 12℅. The original work efficiency must be improved. How many months will it take to finish the project as planned?
3, a project in the project bidding, received a tender from two teams, a day of construction, need to pay a team engineering cost10.2 million yuan, team b engineering cost 05 thousand yuan, the project leading group according to the bidding budget of both parties, have the following plan:
(1) Team A completed the project alone as scheduled;
(2) Team B completed the project alone for 6 days longer than the specified date;
(3) If Party A and Party B work together for 3 days, the remaining projects will be completed by Party B's team alone.
So what kind of construction scheme do you think is the most economical without delaying the construction period? Please explain the reason.
According to the analysis of forestry experts, the secretion produced by leaves under photosynthesis can adsorb some suspended particles in the air, which has the function of dust retention and air purification. As we all know, the average dust retention of Ginkgo biloba leaves in one year is 4 mg less than that of Sophora japonica leaves in one year. If the number of leaves required for the annual dust retention of 65,438+0,000 mg is the same as that of Sophora japonica leaves required for the annual dust retention of 550 mg, find a Sophora japonica leaf.
Students from Class 5.8 (1) go to the tourist area by bus on weekends. The tourist area is 0/20km away from the school/kloc-. Some students take the local train first. 1 hour later, others take the express train. As a result, they arrived at the tourist area at the same time. It is known that the speed of the express train is 1.5 times, so we need the speed of the express train.
3. Choose the third edition of the third grade olympiad math problem.
1, People Machinery Factory processes a batch of parts, 20% of which are processed in Workshop A, 25% in Workshop B, 40% in Workshop C, and 3,600 parts are unprocessed. How many of these parts are there?
2. Qingfeng Stationery delivered 65,438+00,000 brushes, of which 3/7 brushes are the same as 65,438+0/2 brushes. How many tens of thousands of Qingfeng Stationery have been shipped?
Four children bought a boat for 60 yuan. The first child pays half of the total money paid by other children, the second child pays one third of the total money paid by other children, the third child pays one quarter of the total money paid by other children, and how much does the fourth child pay?
The gas cashier went to a building to collect the gas price difference. When he walked out of the building, the number of unpaid households accounted for 1/8 of the paid households. If two households are charged less, the number of unpaid households accounts for 1/6 of the number of paid households. How many families are there in this building?
5. A workshop produces two parts, part A and part B. Type A parts produce more than type B parts 12, all type B parts are qualified, only 4/5 of type A parts are qualified, and 42 type II parts are qualified. How many type II parts have been produced?
4. Selected for the third year of Olympic Mathematics.
1, both parties ride in opposite directions from two places at the same time. A travels 20 kilometers per hour, and B travels 18 kilometers per hour. When they met, there were still 3 kilometers from the midpoint of the whole journey. How long is the whole journey?
The distance between the two places is 900 kilometers. A trip takes 15 days, and b trip takes 12 days. Now A will leave for two days, and B will catch up with A. How many kilometers do I have to walk to catch up?
3. Party A and Party B set off by bus in A and B, which are 240 kilometers apart, and walked in opposite directions, meeting for 5 hours. If Party A and Party B take the original bus and leave in the same direction in two cities at the same time, with the local train in front and the express train behind, Party A and Party B will meet in 15 hours. Find out the speed of each car.
4. Ship A departs from a dock at an average speed of 16 km per hour. Three hours later, ship B also set off from the same dock in the same direction, 12 hours later, it overtook ship A. Find the speed of ship B.
5. Party A 120 yuan, and Party B has 96 yuan money. A spends 15 yuan every day, and B spends 9 yuan every day. How many days later, two people have the same amount of money left?
6. It takes 5 hours for Xiao Wang to go from City A to City B by motorcycle. It takes 10 hours for Xiao Li to go from B to A by bike. At the same time, two people left two cities face to face. When they met, Xiao Wang was still in B city192km. What is the distance between the two cities?
5. Take the fifth part of the third year Olympic math problem.
1. Party A and Party B cooperate to complete a work. Due to good cooperation, Party A's work efficiency is improved by110, and Party B's work efficiency is improved by 1/5. Party A and Party B cooperate for 6 hours to complete the work, but if Party A does it alone, it needs 165438.
Five students, A, B, C, D and E, stand in a horizontal row with 20 flags in their hands. Now we know that students standing on the right of C * * * hold 1 1 flags, students standing on the left of B * * hold 10 flags, students standing on the left of D * * hold 8 flags, and students standing on the left of E * * hold 16 flags. Who are the five students from left to right? How many flags are there in each?
Xiaoming ran a circle on the 360-meter-long circular runway. It is known that he runs 5 meters per second in the first half and 4 meters per second in the second half. How long did it take him in the second half?
In order to measure the length and speed of the passing train, Xiaoying and Xiaoming brought two stopwatches. Xiaoying used one watch to record the train passing in front of him for 15 seconds, and Xiaoming used another watch to record the train passing from the first telephone pole in front and the second telephone pole in the back for 18 seconds. Knowing that the distance between two telephone poles is 60 meters, we can find out the total length and speed of the train.
Xiaoming walks from home to school in the first half and rides a bike in the second half. Go home from school, take the bus for the first time 1/3, and walk for the second time 2/3. As a result, I spent 20 minutes more time at school than at home. How many kilometers is Xiaoming's distance from home to school?