physics
posted by tiana .
two metra trains are on separate but parallel tracks. One has a speed of 90 km/hr, the other 80 km/hr. Initially, the two trains are 2.71 km apart. How long will it take the two trains to pass each other?

(v1+v2)t=s
t=s/(v1+v2)=2.71/170=0.016 h= 57.4 s.