What are some examples of relative velocity?

Assume you are in a bus moving at $30 \frac{k m}{h}$, and you see another car moving in the same direction at a velocity of $40 \frac{k m}{h}$. To you, the car is simply moving at $\left(40 - 30\right)$$\frac{k m}{h}$ or $10 \frac{k m}{h}$