A train passes a station platform in 36 seconds and a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr what is the length of the platform?
120 m
240 m
300 m
None of these
Explanation:
| Speed =$ \left(54 \times\dfrac{5}{18} \right) $m/sec = 15 m/sec. |
Length of the train = (15 \times 20)m = 300 m.
Let the length of the platform be $ x $ metres.
| Then,$ \dfrac{x + 300}{36} $= 15 |
$\Rightarrow x $ + 300 = 540
$\Rightarrow x $ = 240 m.