Two trains are running at 45km/h and 54km/h cross each other in 12 seconds when they run in opposite direction. When they run in the same direction,the person in the faster train observes that he crosses the other train in 32 seconds. Find the length of the two trains?

Asked by mkp400 | 29th Dec, 2017, 08:35: AM

Expert Answer:

now when the trains run in the same direction 
the difference in speed is 9km/h=2.5m/s
so the fast the train will cover the entire length of the slow train in 32 secs
so distance=2.5x32=80mts
now when the trains run in the different direction 
total speed is 99km/h=27.5m/s
now it takes 12 seconds to pass each other
so total distance=27.5x12=330mts
this distance include the length of both trains
so x+80=330......(x=lenght of the fast train)
so x=250mts

Answered by Arun | 29th Dec, 2017, 05:32: PM