A train 110 m long passes a man, running at 6 kmph in the direction opposite to that of the train, in 6 seconds The speed of the train is

A.  54 km/hr   
B.  60 km/hr
C.  66 km/hr   
D.  72 km/hr
Answer: B

Explanation:

Speed of the train relative to man = (110 / 6 ) m/sec
                       = (110 / 6 x 18 /5) km/hr
                      = 66 km/hr
speed of the train be x kmph.
Relative Speed    =(x + 6 ) kmph.
                           = x + 6 = 66
             x = 60.