68. 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:

✅ The correct answer is option B.
Speed of the train relative to man =

125
m/sec

10

   =

25
m/sec.

2

   =

25
x
18
km/hr

2
5

   = 45 km/hr.
Let the speed of the train be x km/hr. Then, relative speed = (x – 5) km/hr.
x – 5 = 45         x = 50 km/hr.