Question

solve it plsssssssssssssssss

Answer 1

Relative speed = 42-30 = 12 km/h = 12*5/18= 10/3 m/s
Time = total length of both the train / relative speed
                = 84+60 / 10/3

                =43.2seconds





Hope it helps... :)

Answer 2

Distance b/w the trains=84-60=24m.
Speed of the first train in m/s=42x5/18=11.67m/s(approx.)
Now, time taken = distance/speed = 24/11.67=2.05 secs.(approx.)