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

The correct option is B $50$ m
Let length of each train be $x$ meters

Relative motion of the faster train w.r.t. slower train is difference of their speeds,
i.e., $10$ km per hour.

Hence two trains will be clear of each other in $36$ seconds which is the time taken in moving the distance of $2x$ metres @ $10$ km/hr.= $\frac{10\times 5}{18}$

we know that,
$distance=speed\times time$

$\Rightarrow 2x=\frac{10\times 5\times 36}{18}$

$\Rightarrow x=50$

$\therefore$ Length of each train $=50$m