Question 775332
A 100 metres long train is moving at 50 km/hr. An another train is 120 metres long is moving in opposite direction and crosses each other in 6 seconds. Find the speed of the second train?

The sum of lengths of the trains is the distance the second train travels.

100+120m =220m=0.22km

Let speed of second train be x km/h

They are in opposite directions.
effective speed = x+50  km/h

Time = 6 seconds = 6/3600 seconds => 1/600 hours

d=rt

0.22=(x+50)*1/600

multiply by 600

0.22*600 =x+50

132=x+50

x=132-50

x=82 km/h