2. What is average speed? A car travels from point $A$ to point $B$ at a speed of 40 km/h, and returns at a speed of 60 km/h. What is the average speed of the car?
2. If the distance from $A$ to $B$ is $n$, then the average speed on the path $2 A B$ is $V_{\text {avg }}=2 n:\left(\frac{n}{40}+\frac{n}{60}\right)=\frac{240 n}{5 n}=48 \mathrm{km} /$ h.