A fast moving superfast express crosses another pasenger train in 20 seconds. The speed of faster train is 72 km/hr and speeds of slower train is 27 km/h. Also the length of faster ntrain is 100m, then find the length of the slower train if they are moving in the same direction.

$Time=\frac{Sum of length of the two trains}{Difference in speeds}$

$20=\frac{(100+x)}{\frac{25}{2}}$ 

$\Rightarrow$ X=150m