A train 300 metres long takes 40 seconds to cross a platform 900 metres long. The speed of the train in, km per hour is :

A. 102 km/hr

B. 104 km/hr

C. 106 km/hr

D. 108 km/hr

Answer: Option D

Solution(By Examveda Team)

$$\eqalign{ & {\text{Speed of train :}} \cr & = \frac{{900 + 300}}{{40}} \cr & = 30{\text{ m/s}} \cr & {\text{Speed (in km/hr):}} \cr & = 30 \times \frac{{18}}{5} \cr & = 108{\text{ km/hr}} \cr} $$