Question

A person moves with a velocity of 30km/h , 60km/hr and 90km/hr in three equal gaps of distance. Determine the average speed of the person.

Answer 1

$speed = diatance \div time$
30km+60km+90km\3hr

180km\3hr = 60km

Answer 2

The speed of an object to cover the total distance is divided by the number of times different speed engaged to cover the distance by that object is known as the average speed of the object.  

It's a scalar quantity which means it is defined only by magnitude and not direction.

The average speed = Sum of all speed / 3  

Average speed = (30 + 60 + 90) km/hr / 3

Average speed  = 180km/hr / 3

Average speed = 60km/hr