A man complete a journey in 10 hours. He travels first half of the journey at the rate of 21 km/hr and second half at the rate of 24 km/hr. Find the total journey in km.

Solution (By Examveda Team)

$$\eqalign{ & \frac{{\left( {1/2} \right)x}}{{21}} + \frac{{\left( {1/2} \right)x}}{{24}} = 10 \cr & \Rightarrow \frac{x}{{21}} + \frac{x}{{24}} = 20 \cr & \Rightarrow 15x = 168 \times 20 \cr & \Rightarrow x = {\frac{{168 \times 20}}{{15}}} \cr & \Rightarrow x = 224\,km \cr} $$