Question

26. A train travelling at 48 km/hr crosses
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
railway platform is:
1) 200 m 2) 300 m 3) 350 m 4) 400 m​

Answer 1

Let the length of the train traveling at 48 kmph be 2x meters.

And length of the platform is y meters. Relative speed of train=(48+42)kmph=(90×518)=25m/sec;And48kmph=48×518=403m/secAccording to the question,(2x+x)25=12;Or,3x=12×25=300Or,x=3003=100mThen, length of the train=2x=100×2=200m200+y(403)=45600+3y=40×45Or,3y=1800−600=1200Or,y=12003=400mLength of the platform=400m