A train is 250 m long. If the train takes 50 second to cross a tree by the railway line, then the speed of the train on Km /hr is :

A. 9 km/hr

B. 5 km/hr

C. 18 km/hr

D. 10 km/hr

Answer: Option C

Solution(By Examveda Team)

$$\eqalign{ & {\text{Speed}} = \frac{{{\text{Distance}}}}{{{\text{Time}}}} \cr & {\text{Speed}} = \frac{{250}}{{50}} = 5{\text{ m /s}} \cr & {\text{Speed}} = 5 \times \frac{{18}}{5} = 18{\text{ km /hr}} \cr} $$