A train 108 meter long moving at a speed of 50 km/hr crosses a train 112 m long coming from opposite direction in 6 seconds. The speed of the second train is?

Assume the speed of the second train be x km/hr.

so relative speed is = ( x + 50) km/hr.

                            = ((x + 50) * 5/18) m/sec

                            =  (250 + 5x)/18 m/sec

Total distance covered = (108 + 112) = 220 meter

so 220/((250 + 5x)/18) = 6

    (220 * 18)/(250 + 5x) = 6

     250 + 5x = 660

     x = 82 km/hr