Question

The average speed of the train in the onward journey is 25% more than tat in the return journey.The train halts for one hour on reaching the destination.The total time taken for the complete to and fro journey is 17 hours,covering a distance of 800 km.The speed of the train in the onward journey is:

Answer 1

Let the speed in return journey be $x$ km/hr.

Then speed in onward journey $=\frac{125x}{100}=\left(\frac{5x}{4}\right)$ km/hr.

Average speed $=\frac{2\times \frac{5x}{4}\times x}{\frac{5x}{4}+x}=\frac{10x}{9}$ km/hr.

$\therefore$ $(800\times \frac{9}{10x})=16$

$x=\frac{800\times 9}{16\times 10}=45$.

Speed in onward journey $=(\frac{5}{4}\times 45)$ km/hr $=56.25$ km/hr.