Two trains cross each other in 12 seconds, when they travel in opposite directions and they take 60 seconds when they travel in the same direction. The possible speeds of the trains, (in m/sec). can be:

20, 30

Speed of 1st train = a km/h

Speed of 2nd train = b km/h

Relative speed when moves in same direction = ( a-b) km/h

Relative speed when moves in opposite direction = ( a+b) km/h

& Distance = D km

According to question ,

( a + b) × 12 = D     ---------(1)

( a - b) × 60 = D      ---------(2)

( a + b) × 12 = ( a - b) × 60

( a + b)  = ( a - b) × 5

4a = 6b

a : b = 3 : 2

So , Possible value of Speed of A & B is 30 & 20 respectively .