# 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?

A. 254 m
B. 250 m
C. 240 m
D. 280 m

Solution:

$\left. \begin{array} { l } { \text { Speed } = ( 54 \times \frac { 5 } { 18 } ) m / sec = 15 m / sec } \\ { \text { Length of the train } = ( 15 \times 20 ) m = 300 m } \\ { \text { Let the length of the platform be } x \text { metres. } } \\ { \text { Then, } \frac { x + 300 } { 36 } = 15 } \\ { \Rightarrow x + 300 = 540 } \\ { \Rightarrow x = 240 m } \end{array} \right.$