How many seconds will a 500 meter long train take to cross a man walking with a speed of 3 krn/hr in the direction of the moving train if the speed of the train is 63 km/hr ?

A.  25   
B.  30
C.  40   
D.  45
Answer: B

Explanation:

Speed of train relatively to man = ( 63 - 3)km/hr
                                               = 60 km /hr
                                               = (60 x 5 / 18)m/sec
                                              = (50 /3) m/sec
Time taken to pass the man = (500 x 3 / 50)sec
                                          = 30 sec.