(A) 6.7 km
(B) 8.2 km
(C) 7.5 km
(D) 9.3 km
Correct Option is: B
Speed of the train = 25 m/s.
Length of the chunk = 0.8 km
= 800 meters
Time taken to cross the chunk = 6 minutes
= (6*60) seconds
= 360 seconds
Let the length of the train be y meters.
Time taken by the train to cover (800 + y) meters at 25 is 360 seconds
i.e., distance = speed x time
(800+y) = 25 x 360
800+y = 9000
y = 8200 m
i.e., y = 8.2 km
Hence the length of the train is 8.2 km