A train passes a 50 meter long platform in 14 seconds and a man standing on platform 10 seconds.The speed of the train is?

A. 24 km/hr

B. 36 km/hr

C. 40 km/hr

D. 45 km/hr

Answer: Option D

Solution(By Examveda Team)

$$\eqalign{ & {\text{Distance travelled in 14 sec}} \cr & {\text{ = 50 + }}l \cr & {\text{Distance travelled in 10 sec}} \cr & {\text{ = }}l \cr & {\text{So speed of train}} \cr & {\text{ = }}\frac{{50}}{{14 - 10}}{\text{m/sec}} \cr & {\text{ = }}\frac{{50}}{4} \times \frac{{18}}{5}{\text{km/hr}} \cr & {\text{ = 45 km/hr}} \cr} $$