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. $45$ km/hr
• B. $50$ km/hr
• C. $40$ km/hr
• D. $55$ km/hr

Answer 1

The correct option is B $50$ km/hr

Let the speed of the train be $x$ km/hr.
Then, relative speed $=(x-5)$ km/hr
Distance $=$ Speed $\times$ Time
$\Rightarrow \frac{125}{1000}=(x-5)\times \frac{10}{3600}$
$\Rightarrow 100(x-5)=125\times 36$
$\Rightarrow x=50$ km/hr
Hence, speed of the train is $50$ km/hr.