Quadratic Word problem

Question

An astronaut drops a rock off the edge of a cliff on the Moon. The distance, d(t), in meters, the rock travels after t seconds can be modeled by the function d(t)=0.8t^2. What is the average speed, in meters per second, of the rock between 5 and 10 seconds after it was dropped

(A)12

(B)20

(C)60

(D)80

Answer 1

Apply the average rate of change formula

 

 

  d(10) - d(5)

_____________

       10 - 5