Two goods train each 500 m long are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.

12 sec

24 sec

48 sec

60 sec

Explanation:

Relative speed =	= (45 + 30) km/hr
	=$ \left(75 \times\dfrac{5}{18} \right) $m/sec
	=$ \left(\dfrac{125}{6} \right) $m/sec.

We have to find the time taken by the slower train to pass the DRIVER of the faster train and not the complete train.

So, distance covered = Length of the slower train.

$\therefore$ Distance covered = 500 m

$\therefore$ Required time = $\left(500 \times\dfrac{6}{125} \right) $= 24 sec.