A train x running at 74 km/h crosses another train y running at 52 km/h in the opposite direction in 12 seconds. If the length of y is two-thirds that of x, then what is the length of x (in m)?

252

Relative speed (74 + 52) = 126 km/h

( when moves in opposite direction )

= 126 × \(\frac{5}{18}\)

= 35 m/s

Time taken to cross each other 12 second

Distance = Speed × Time

Total distance covered =  12 × 35 = 420 m

Given :-  The length of y is two-thirds that of x

Let, the length of the train x is X meter

Accordingly,

(X +  \(\frac{2X}{3}\) ) = 420    

 X = 420 × \(\frac{3}{5}\)

 X = 252

So ,  The length of the train X is 252 m