tina swims in a pool of length of 80m and then come back to the starting point in 8s.Find-1) Average speed 2) Average velocity.

Dear Student,
Total distance travelled in to and fro journey of tina, d = 80m + 80m = 160m
Total time taken, t = 8s
Since, tina returns back to the starting point, displacement,  r = 0m
$$\begin{gathered} 1). Average speed = \frac{total dis\tan ce travelled}{total time taken}=\frac{d}{t}=\frac{160m}{8s}=20 m/s \\ 2). Average velocity = \frac{total displacement}{total time taken}=\frac{r}{t}=\frac{0}{8s}=0 m/s \end{gathered}$$

Regards