A train travelling at a speed of  60 kmph passes a pole in 9 seconds. The time taken to the train to cross a platform, of  250 mts long is

Speed of train $=60\text{kmph}=60\times \frac{5}{18}=\frac{50}{3}\text{m}/\sec$

Time taken $=9\text{\hspace{0.17em}seconds}$

Length of train $=\text{speed}\times \text{time}=\frac{50}{3}\times 9=150\text{m}$

Total distance $=\text{length\hspace{0.17em}of\hspace{0.17em}train}+\text{length\hspace{0.17em}of\hspace{0.17em}a\hspace{0.17em}platform}$

$=150\text{m}+250\text{m}=400\text{m}$

Time taken $=\frac{\text{total distance}}{\text{Speed of train}}=\frac{400\times 3}{50}=24\sec$