A particle travels on a straight line and it's position(x) at a function of time(t) is shown. The average speed for the whole time interval is

Dear student,

Distance travelled from t=0s to t=2s is 20m
Then particle stops for some time and later returns to the starting point
Distance travelled from t=2s to t=10s is 20m
Finally particle moves 10m in negative direction, stops for some time and returns back to origin.
Distance travelled from t=10s to t=12s is 10+10m=20m
Hence total distance travelled=60m.

Hence average speed=

Regards.