A bridge is 1000 meters long, a train is 80 meters long, and the speed is 50 m / s In a hurry Solving linear equation with one variable

A bridge is 1000 meters long, a train is 80 meters long, and the speed is 50 m / s In a hurry Solving linear equation with one variable

Time = (1000 + 80) / 50 = 21.6 seconds time = (1000-80) / 50 = 18.4 seconds

An iron bridge is 1000 meters long. A train passes through the bridge. It takes one minute for the train to get on the bridge and then completely cross the bridge. The time for the whole train to be completely on the bridge is 40 seconds (from the rear of the train to the front of the train about to get off the bridge). How about the speed and length of the train?

1 minute = 60 seconds, all pass: S1 = l bridge + L, T1 = 60s, all on the bridge: S2 = l bridge - L, T2 = 40s, suppose the speed of the train is v m / s, the length of the train is l m, then 60s × v = 1000m + l40s × v = 1000m − L, the solution is: v = 20m / s, l = 20m