Engineering problems 1. Both parties can finish a work within 30 days. After 6 days of cooperation, Party A left and Party B continued to do it for 40 days. How many days will it take if this work is done by A or B alone?
2. For a project, 10, team A will finish it alone, and team B will finish it alone in 30 days. Now the two teams cooperate, during which team A has a rest for 2 days and team B has a rest for 8 days (there is no such thing as two teams having a rest on the same day). How many days did it take from the beginning to the end?
3. Two engineering teams, A and B, built roads, and finally paid 8400 yuan according to the workload. According to the original work efficiency of the two teams, team B should get 5040 yuan. In fact, from the 5th day, the working efficiency of Team A has been improved by 1 times, so that Team A can finally get more 960 yuan than originally planned. So how many days will it take for the two teams to complete the road construction task?
Encountered a problem 1. An express train is 170 meters long and travels at a speed of 23 meters per second, while a slow train is 130 meters long and travels at a speed of 18 meters per second. How many seconds does it take for the express train to catch up with the local train from behind?
2. The distance between A and B is 100 km, and both A car and tractor travel from A to B. When the car starts, the tractor has already started15km; When the car arrived at B, the tractor was 0/0 kilometers away from B/KLOC ... So how many kilometers away from B did the car catch up with the tractor?
The circumference of the circular runway is 500 meters. Party A and Party B set out at the same time and placed them clockwise along the circular runway. Party A runs 50 meters per minute and Party B runs 40 meters per minute. They should stop to rest every 200 meters 1 minute. How many minutes does it take for Party A to catch up with Party B for the first time?
4.A and B are driving in opposite directions at the same time, meet at a distance of 54 kilometers from B, return immediately after arriving at the other station, and meet at a distance of 42 kilometers from A ... Excuse me, how many kilometers is there between A and B?
The problem of crossing the bridge is 1. A train passes the 6700-meter-long Nanjing Yangtze River Bridge. The train conductor140m, and the train runs 400m per minute. How many minutes does it take for this train to cross the Yangtze River Bridge?
A train is 200 meters long, and it takes 30 seconds for the whole train to cross a 700-meter-long bridge. How many meters does this train travel per second?
A train is 240 meters long. This train runs 15 meters per second. It takes 20 seconds from the front of the train to the whole car leaving the cave. How long is this cave?
The above are the examples of primary school Olympic mathematics that I compiled, hoping to help everyone.