Two trains are running in opposite directions with the same speed. If the length of each train is 120 metres and they cross each other in 12 seconds, then the speed of each train (in km/hr) is:

Let the speed of each train be x m/s. Since the trains are moving in opposite directions, their relative speed is 2x.

Total length to be crossed = length of train 1 + length of train 2 = 120 + 120 = 240 meters.

Using the formula:

Distance = Speed × Time240 = 2x × 12=> x = 10 m/s

Convert the speed to km/hr:

1 m/s = 18/5 km/hr=> 10 m/s = 10 × (18/5) = 36 km/hr

Hence, the speed of each train is 36 km/hr.