Ravi and Ajay start simultaneously from a place A towards B, 60 km apart. Ravi's speed is 4 km/hr less than that of Ajay, after reaching B, Ajay turns back and meet Ravi at a place 12 km away from B, Ravi's speed is :

Answer: Option C

Let the speed of Ravi = x km/hr
Then Ajay's speed will be = (x + 4) km/hr
Total distance, covered by Ajay :
= (60 + 12) km
= 72 km
Total distance, covered by Ravi :
= (60 - 12) km
= 48 km
According to the question,
They run at same time
$$\begin{array}{rl}& \Rightarrow \frac{72}{(x+4)}=\frac{48}{x}\\ & \Rightarrow 72x=48x+192\\ & \Rightarrow 24x=192\\ & \Rightarrow x=8\text{ km/hr}\end{array}$$
Therefore, Ravi's speed = 8 km/hr