A train having 15 bogies develops a technical snag in the carriage connecting its 5th and 6th
bogies from the engine (i.e. front). The guard at the rear (i.e. the
last bogie) notices the snag and immediately starts running towards it
at a speed of 14 mps on the top of the roof. After some time, the
driver’s assistant notices the fire and starts running towards it on the
top of the roof at a speed of 10 mps. The length of each bogie is 35 m
and the distance between any two bogies is negligible. If the train is
running at a speed of 16 mps, how much time after the guard did the
assistant notice the snag, if it is known that both of them reached the
snag at the same time.

1) 7.5
2) 10
3) 15
4) CBD