Trains Boats and Streams Practice Test 5 with solutions

Let the length of the train = x m
Speed = y kmph
Time = 10 seconds
= $\frac{10}{60}$ = $\frac{1}{6}$ hrs
So, speed = $\frac{\mathit{d}}{\mathit{t}}$ = $\frac{\mathit{x}}{\frac{1}{6}}$ = 6x mph
Now length of the platform = 200m
Total length = (x + 200) m
Time taken by the train to cross the platform
= $\frac{20}{60}$ = $/3$ hrs
So, speed = $\frac{\mathit{x}+200}{\frac{1}{3}}$
= 3x + 600 mps ……(ii)
From equation (i) and (ii) we get,
6x = 3x + 600
3x = 600
x = 200
So, the length of the train 200 meter is 200 m