AFCAT II 2015 Solved Paper

Let length of the train is x.
Distance = 12 km = 12000 m
Time = 10 min = 10 × 60 = 600 sec
Speed of train =

12000

600

=20m / sec
when train passes a telegraph post it covers distanceequal to its length.
using distance = time × speed
x = 6 × 20 = 120 m