Question

men ar running in a line along a road with velocity 9km/h behind one another​

Answer 1

Answer:

9km/h

Explanation:

bro take observer's speed as v

assume that at starting point observer,cyclist and a man are at same point

now apply relative motion and time taken by cyclist ,man and observer is same

so ,

distance between observer and cyclist =30m

relative speed=v+18

distance between observer and man=20m

relative speed=v+9

30/v+18=20/v+9

3(v+9)=2(v+18)

3v+27=2v+36

v=9