Question

Can the average speed of moving can be 0

Answer 1

no the average speed can never be 0 only average velocity can be 0

Answer 2

Speed is a scalar quantity it doesn't depend upon the direction in which you move

Speed=distance/time

In whatever path you move, the total distance goes on increasing and it will never be zero ,as well as time also. so the ratio of distance to time will be always positive.

So ,if the body is stationary with respect to time ,then only average speed will be zero because the distance moved is zero .In remaining all cases, the average speed will be positive.

But the average velocity can be zero if the displacement = 0