A train 125 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 10 seconds. The speed of the train is:

To solve this problem, we first need to convert all the measurements to a common unit. In this case, we'll use meters and seconds.

Step 1: Convert the length of the train to meters. It's already given as 125 meters, so no conversion is needed.

Step 2: Convert the speed of the man to meters per second. 5 km/hr is approximately 1.39 meters per second (5,000 meters per 3,600 seconds).

Step 3: Calculate the relative speed of the train to the man. The train passes the entire length of itself (125 meters) in 10 seconds, so its speed relative to the man is 125 meters / 10 seconds = 12.5 meters per second.

Step 4: Add the man's speed to the relative speed to get the speed of the train. 12.5 meters per second + 1.39 meters per second = approximately 13.89 meters per second.

Step 5: Convert the speed of the train back to kilometers per hour.