A motorcyclist completes a certain journey in 5 hours. He covers one-third distance at 60 km/hr and the rest at 80 km/hr. The length of the journey is :

A. 180 km

B. 240 km

C. 300 km

D. 360 km

Answer: Option D

Solution(By Examveda Team)

Let the length of the journey be x km.
Then,
$$\eqalign{ & \Rightarrow \frac{{\frac{1}{3}x}}{{60}} + \frac{{\frac{2}{3}x}}{{80}} = 5 \cr & \Rightarrow \frac{x}{{180}} + \frac{x}{{120}} = 5 \cr & \Rightarrow \frac{{5x}}{{360}} = 5 \cr & \Rightarrow x = 360\,\text{ km} \cr} $$