A train is 125 m long. If the train takes 30 sec to cross a tree by the railway line, then the speed of the train is :

A. 14 km/hr

B. 15 km/hr

C. 16 km/hr

D. 12 km/hr

Answer: Option B

Solution(By Examveda Team)

$$\eqalign{ & {\text{Speed : }} \cr & = {\text{ }}\frac{D}{T} \cr & = \frac{{125}}{{30}}{\text{m /sec}} \cr & {\text{ = }}\frac{{125}}{{30}} \times \frac{{18}}{5}{\text{ km /hr}} \cr & {\text{ = 15 km /hr}} \cr} $$