arithmetic - two train each 500 m long are running in opposite directions on parallel tracks if their speeds are 45 kmhr and 30 kmhr respectively the time taken by the slower train to pass the driver of the faster one is - skillgun

Relative speed = 45+30 = 75 km/hr = 750/36 m/s = 125/6 m/s
We are calculating the time taken by the slower train to pass the driver of the faster one. Hence the distance = length of the smaller train = 500 m
Time = distance/speed = 500/(125/6) = 24 s