In how many different ways, the letters of word 'FINANCE' can be arranged?

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 × Time\n240 = 2x × 12\n=> x = 10 m/s

Convert the speed to km/hr:

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

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