Answer:
Overall velocity of a person is 1.66 

Step-by-step explanation:
Let the forward displacement of the person is taken as positive and backward displacement is taken as negative.
You walk forward 10 meters,
displacement = 
 = 10 meter
 = 10 meter
You walk backward 5 meters,
displacement = 
 = -5 meter
 = -5 meter
You walk forward 10 meters,
displacement = 
 = 10 meter
 = 10 meter
Total displacement = s = 

s = 15 -5 +15
s = 25 meter
Total time taken is given by,
t = 15 second
Overall velocity is the average velocity of a person and it is given by,
Average velocity = 

Average velocity = 

Average velocity = 1.66 

Thus, overall velocity of a person is 1.66 
