Question

A train travelling at 48 km/hr completely corsses another train having half its length and travelling in opposite direction at 42 km/hr. in 12 seconds. It also passes a railway platform in 45 seconds. The length of the platform is ___

Answer 1

Then, the length of the second train is (x) metres.2
Relative speed =$(48+42)kmph=(90\times 5)m/sec=25m/sec.18$
$\therefore \frac{[+(2\left)\right]}{xx}=12$ or 3
x= 300 or = 200.x
252
Length of first train = 200 m.
$\therefore$
Let the length of platform be metres.
y
Speed of the first train =$(48\times 5)$
$m/sec=\frac{40}{3}m/sec$.
18
(200 + ) x
$\therefore y3$
$\frac{3}{40}=45$
600 + 3 = 1800
$\Rightarrow y$
$=400m$.
$\Rightarrow y$