Question

A train 125 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 10 seconds. The speed of the train is:

• A. 45km/hr
• B. 50km/hr
• C. 54km/hr
• D. 55km/hr

Answer 1

The correct option is B

50km/hr

Speed of the train relative to man $=\left(\frac{125}{10}\right)$ m/sec
$\left(\frac{25}{2}\right)$ m/sec.
$(\frac{25}{2}\times \frac{18}{5})km/hr$
= 45 km/hr.
Let the speed of the train be $\times$ km/hr. Then, relative speed = (x - 5) km/hr.
$\therefore x-5=45\Rightarrow x=50km/hr.$