Correct Answer: 49 kmph
Explanation:
Speed of the train relative to man
= (125/10) m/sec = (25/2) m/sec.
[(25/2) x (18/5)] km/hr = 45 km/hr.
Let the speed of the train be 'x' km/hr.
Then, relative speed = (x - 4) km/hr.
x - 4 = 45 => x = 49 km/hr.