19 m/s is the average velocity if the initial velocity of an object is 10 m/s and the final velocity is 28 m/s.
Step-by-step explanation:
The initial and final velocity is given and the average velocity is asked, which can be calculated by the following method,
Given that initial velocity = 10 m/s and final velocity = 28 m/s
As we know that the average velocity =

Although,

But here, there is only given initial and final velocity therefore it will be simply an average of the two.

Therefore, the average velocity of the object is 19 m/s.