A train 108 m long moving at a speed of 50 km/hr crosses a train 112 m long coming from opposite direction in 6 seconds. The speed of the second train is:

48 km/hr

54 km/hr

66 km/hr

82 km/hr

Explanation:

Let the speed of the second train be $ x $ km/hr.

Relative speed	= $\left( x + 50\right)$ km/hr
	=$\left[\left( x + 50\right) \times \dfrac{5}{18}\right] $sec
	=$\left[\dfrac{250 + 5x}{18}\right]$sec.

Distance covered = (108 + 112) = 220 m.

$\therefore \frac{220}{\left(\dfrac{250 + 5x}{18} \right) } $= 6

$\Rightarrow 250 + 5 x $ = 660

$\Rightarrow x$ = 82 km/hr.