(A) 8.78 Sec
(B) 9.87 Sec
(C) 11.2 Sec
(D) 23.4 Sec
Correct Option is: A
Length of the train = 400m
Speed of train = 124 km/hr
Speed of person = 40 km/hr
Relative speed (speed of trai relative to man) = (124 + 40) km/hr
= 164 km/hr
[As the train and the running person are moving in opposite direction,therir speed values are added to find
the relative speed.]
Convert km/hr into m/s
164 km/hr = 164 * 5 / 18
= 820/18
= 45.55 m/s
We know speed = distance / time
Therefore time taken by the train to cross the running person = time taken by the train to cover 400m at a
relative of 45.55 m/s
= 400 / 45.55
= 8.78 sec.