# What is the time (in seconds) which they take to cross each other?

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Two trains 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. What is the time (in seconds) which they take to cross each other?

posted Jan 19, 2016

Relative speed=s=60+40=100kmph=100*5/18m/sec=250/9m/sec
Distance=d=140+160=300m
Time=t=d/s
t=(300)/(250/9)=10.8sec
Ans :Two trains cross each other in 10.8 sec

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