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Mathematical Olympics in Grade Seven
Class 5 (1) students subscribed to newspapers in 2002 ***68 points. According to the monitor's statistics, they found: "One copy for every student (China Youth Daily), one copy for every four students (Primary Mathematics Daily) and one copy for every six students (Technology and Expo)." How many people are there in Class Five (1)?

Class A and Class B leave school for the park at the same time. The walking speed of Class A is 4 kilometers per hour, and that of Class B is 3 kilometers per hour. There is a car in the school. When people are in the car, the speed is 40 kilometers per hour, and when they are empty, the speed is 50 kilometers per hour. This car can just take a class of students, and the distance from the school to the park is only 24.9 kilometers. In order to let all the students in these two classes arrive at the park in the shortest time. (Getting on and off time is not counted)

The students of Class A and Class B leave for the park at the same time. The walking speed of Class A is 4 kilometers per hour, and that of Class B is 3 kilometers per hour. The school has a car with a speed of 48 kilometers per hour, which can just carry a class of students. In order to make these two classes arrive in the shortest time, what is the walking distance ratio between Class A students and Class B students?

1.A and B have special training on the same oval track: they run from the same place in the opposite direction at the same time, and each person accelerates to run the second lap immediately after finishing the first lap and reaching the starting point. On the first lap, B's speed is two-thirds of A's, A's speed on the second lap is one-third higher than that on the first lap, and B's speed on the second lap is one-fifth higher. It is known that the second intersection of A and B is 90 meters away from the first intersection/kloc-0. How long is this oval runway?

2. Party A, Party B and Party C have done a job, which was originally planned to be done in the order of Party A, Party B and Party C, and happened to be completed in an integer number of days. If we do it in the order of C, B and A, it will take half a day longer than originally planned. If we take turns to do it in the order of C, A and B, it will take one third longer than originally planned. It is known that it will take 13 days for Party A to complete this work alone. How many days will it take for Party A, Party B and Party C to finish this work together?