Question

A train passes two bridges of lengths 800 m and 400 m in 100 seconds and 60 second respectively. The length of the train is:

Answer 1

Let the length of train be 'x' m.

So the distance covered in first station =800 m + the length of train

Time=100sec

Speed=800+x/100. -1

The distance covered in second station =400+x

Time=60 sec

Speed=400+x/60. -2

Since the speed is equal , equations 1 and 2 are equal.

Equating 1 and 2,

(800+x)*60=(400+x)*100. Cross multiply

48000+60x=40000+100x

8000=40x

x=8000/40=200

Hence the length of train is 200 m.