Question

The speed of an ordinary train is $x$ km per hr and that of an express train is $(x+25)$ km per hr. Find the time taken by each train to cover $300$ km. If the ordinary train takes $2$ hrs more than the express train .calculate speed of the express train

Answer 1

Ordinary train speed = x km/hr ; (x+12)hrs

express train speed = (x+25)km/hr ; +hours

distance = 300 km.

$\therefore x=\frac{300}{tt2}$ & $x+25=\frac{300}{t}$

$\Rightarrow \frac{300}{x+25}+2=\frac{300}{x}\Rightarrow t=\frac{300}{x+25}$

$\Rightarrow x(300+2x+50)=300(x+25)$

$\Rightarrow 350x+2x^2=300x+7500$

$2x^2+50x-7500=0$

$x=50,-75$

Neglect -ve

$\therefore$ (x+25) = 75 km/hr (speed of express train)