The bus and the van run in opposite directions from the midpoint of A and B at the same time. After 5 hours, the bus arrives at A, and the van is 60 kilometers away from B. It is known that the speed ratio of the van to the bus is 5: 7. What's the distance between a and b? (Answer in four ways)
Let's assume that their common speed ratio is X, the speed of passenger cars is 7x, and the speed of freight cars is 5x. We can get:
7x*5-5x*5=60，
The solution is x=6,
Again: the speed of the bus is 42 meters per second, and the speed of the truck is 30 meters per second.
The distance between Party A and Party B is: 30*5+60+42*5=420m.
Second, suppose that the distance between Party A and Party B is xm,
x/2-60=5*x/2/5*5/7，
The solution is x = 420 m.
Thirdly, suppose that the distance between Party A and Party B is xm,
x/2/5/x-60/5=7/5，
The solution is x = 420 m.
Fourthly, let the speed of passenger cars be xm/s and the speed of freight cars be 5/7x.
5x-60=5/7x*5，
The solution is x = 42m/s,
The distance between Party A and Party B is 2 * 5x = 420m.