we know that a particle cannot travel distance at particular instance but how instantaneous speed exist?

Answer 1

Instantaneous speed means speed at a particular instance not the distance travelled in that instant of time.If a

body is accelerating its velocity is continuosly increasing?yes/no??

So,it will possess a instantaneous velocity(same applies if a body is moving with a constant velocity)...

Ex:Watch the speedometer of a 2 or 4 wheeler.

 @Gopikrishna Mogasati