5. A train took 9 seconds to pass a signal light on a utility pole, and it took 35 seconds to cross a 520-meter-long iron bridge. The length of the train is (
) meters
180
【Answer】The length of the train is 9 times its speed; therefore, 520 meters is 35-9=26 times its speed; so the speed of the train is 20 meters/second; hence the length of the train is 180 meters