• # question_answer A train 108m long moving at a speed of 50 km/h crosses a train 112m long coming from the opposite direction in 6 seconds. The speed of the second train is A)  48 km/h            B)  54 km/h C)  66 km/h            D)  82 km/h

[d] Let the speed of the second train be x km/h The relative speed = (50 + x) km/h These trains will cross each other in a time equivalent of covering a distance equal to 108 + 112, i.e. 220 meters in 6 seconds, running a speed of (50 + x) km/h $\therefore$ $\frac{1}{50+x}\times \frac{220}{1000}=\frac{6}{3600}$ $\Rightarrow$ $x=82$ $\therefore$ The speed of the second train = 82 km/h.