A bridge is 4200m long and a train is 600m long. It passes through the bridge at the speed of 1200m per minute. How long does it take from the front of the train to the rear of the train to leave the bridge?

A bridge is 4200m long and a train is 600m long. It passes through the bridge at the speed of 1200m per minute. How long does it take from the front of the train to the rear of the train to leave the bridge?

From v = s / T, we can get that:
t=s/v=(4200m+600m)/(1200m/min)=4min
A: it takes 4 minutes from the front to the rear

A 180 m long train passes a 600 m long bridge at a speed of 20 m / s. The time required for the train to pass the bridge is calculated

The distance of train passing through the bridge: S = s Bridge + s car = 600m + 180m = 780m, ∵ v = St ∵ the time of train passing through the bridge: T = SV = 780m20m / S = 39s. A: the time of train passing through the bridge is 39s

It took one minute for a train to pass through a cave at the speed of 15 m / s. It is known that the train is 200 m long. How long is the cave?

15x60-200
=700M
I hope I can help you,