A passenger car and a train run in the same direction on parallel tracks. The length of a passenger car is 200 meters, and that of a freight car is 280 meters The speed of the bus is 1200 meters per second, and the speed of the train is 720 meters per second. How many seconds is the crossing time of the two trains? (solution of equation)

A passenger car and a train run in the same direction on parallel tracks. The length of a passenger car is 200 meters, and that of a freight car is 280 meters The speed of the bus is 1200 meters per second, and the speed of the train is 720 meters per second. How many seconds is the crossing time of the two trains? (solution of equation)

Time in the same direction (200 + 280) / (1200-720) = 1 second
Phase time (200 + 280) / (1200 + 720) = 0.25 seconds
Set the crossing time X
① In the same direction
(1200-720)x=200+280
x=1
② Opposite
(1200+720)x=200+280
x=0.25