The playground is 400 meters long. A practice cycling, riding an average of 350 m per minute; B practice running, running an average of 250 meters per minute. How long does it take for two people to meet for the first time from the same place and in the opposite direction at the same time? How long did it take to meet again? ?
3. Two candles of the same length, the thick one can burn for 3 hours, and the thin one can burn for 8/3 hours. When the power goes out, two candles are lit at the same time, and when the phone calls in, they are blown out at the same time. The thick one is twice as long as the thin one.
4. The number of people in Workshop A is 30 less than 4/5 of Workshop B. If 10 people are transferred from Workshop B to Workshop A, then the number of people in Workshop A is 3/4 of Workshop B. Find the original number of people in each workshop. ?
5. A project needs to be completed within the specified date. If Team A did it, it would be finished on schedule. If it is done by team B, it will take more than 3 days to finish. If Party A and Party B work for two days first, and then team B does it alone, it can be completed on schedule. How many days is the specified date? ?
6. Distribute a batch of books to students? If each person has three copies, what about the remaining eight copies? If everyone has five copies. So the last person will get less than three copies? How many books and students are there?