Step-by-step explanation:
Given that,
A student travels 11 m north and then turns around to travel 25 m south.
Total time, t = 12 s
The total distance or the total path covered by the student is equal to 11 m + 25 m = 36 m
Displacement of the student or the shortest path covered is d = 25-11 = 14 m
(a) The student's average speed = total distance/total time
![s=(36\ m)/(12\ s)\\\\s=3\ m/s](https://img.qammunity.org/2021/formulas/physics/high-school/mvizu5bvs8ags6i6qh35mnk5v5kqvbj6rj.png)
(b) The student's average velocity = total displacement/total time
![v=(14\ m)/(12\ s)\\\\v=1.17\ m/s](https://img.qammunity.org/2021/formulas/physics/high-school/8h83q0q9mxyipgqhktz5zvph9as2w727ww.png)