The train, moving evenly at a speed of 75 km / h, passes a pedestrian walking parallel to the tracks at a speed of 3 km / h

The train, moving evenly at a speed of 75 km / h, passes a pedestrian walking parallel to the tracks at a speed of 3 km / h towards the train, in 30 seconds. Find the length of the train in meters.

1. Let’s calculate the speed of the train relative to the pedestrian moving towards it.
75 km / h + 3 km / h = 78 km / h.
2. Determine how much is 30 seconds in hours.
30 sec = 30: (60 * 60) h = 30/3600 = 1/120 h.
3. Let’s calculate the length of the train.
78 km / h * 1/120 h = 0.65 km.
4. Determine how many meters is 0.65 km.
0.65 * 1000 = 650 meters.
Answer. The train length is 650 meters.