Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is:

50 m

72 m

80 m

82 m

Explanation:

Let the length of each train be $ x $ metres.

Then, distance covered = 2$ x $ metres.

Relative speed = (46 - 36) km/hr

=$ \left(10 \times\dfrac{5}{18} \right) $m/sec

=$ \left(\dfrac{25}{9} \right) $m/sec

$\therefore \dfrac{2x}{36} $=$ \dfrac{25}{9} $

$\Rightarrow$ 2$ x $ = 100

$\Rightarrow x $ = 50.