Now I want to drain all the water in a pond, but at the same time, the water flows into the pond at a constant speed. If 8 pumps are used, it can be drained in 10 day; It can be discharged in 20 days with 6 pumps. Q: How many identical pumps do you need to pump water in five days?
3. In a garment processing workshop, Group A can process 8 coats or 9 pairs of trousers every day, Group B can process 6 coats or 8 pairs of trousers every day, and Group C can process 6 coats or 7 pairs of trousers every day. How many sets of clothes can three groups of cooperation 15 days produce at most?
4. Container A contains 150g of 4% salt water, and container B contains a certain amount of salt water. Take out 450g of salt water from container B, put it into container A, and mix it into 8.2% salt water. What is the concentration of container b?
5. A pool is equipped with two water inlet pipes, A and B, and the water intake of the second pipe is 1.6 times that of the first pipe. When the empty pool is filled, the first pipe starts to fill the water in the pool, then the second pipe is opened, and the rest is filled by the second pipe alone, with a total time of12min15s. How long has the nail tube been open?
6. A pool of water will be filled in 5 hours when the pipes of Party A and Party B are opened at the same time, and will be filled in 4 hours when the pipes of Party B and Party C are opened at the same time. It will take 6 hours to open Party B's pipeline first, and it will take 2 hours for Party A and Party C to fill it up. B how many hours can a person drive to fill it?
7. Two trains leave from Party A and Party B relatively simultaneously. It takes 20 hours for the express train and 30 hours for the local train. 15 hours later, the two cars meet. It is known that the express train stopped for four hours and the local train stopped for several hours.
8. For a project, it takes 10 days for Team A to do it alone, and 30 days for Team B to do it alone. Now the two teams cooperate, during which team A has a rest for 2 days and team B has a rest for 8 days (not on the same day). How many days did this project take?
9. The ship sails at the same speed. It takes 3 days and nights from city A to city B, 4 days and nights from city B to city A, and how many days does it take for the raft to drift from city A to city B?
There are 10g, 20g and 30g water in three test tubes A, B and C, respectively. Pour a certain concentration of 10g saline into A, mix and take out 10g saline, and then take out 10g saline in C..
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