Good evening experts,
Could you please help me with the following questions?

Dear Student,
The displacement - time graph is as follows:

(i). Total distance travelled in interval 1s to 5s = 18 - 6 = 12 m

(ii). Total displacement from 1 to 5s, d = 18 - 6 = 12m
Total time taken = 5 - 1 = 4 s
Average velocity, $v_{avg}=\frac{total displacement}{total time}=\frac{12}{4}=3 m/s$

Regards