Question

The graph shows the distance in miles of a runner over x hours. What is the average rate of speed over the interval [9, 11]?

Answer 1

For this case what you should see is that for the interval [9, 11] the behavior of the function is almost linear.
 Therefore, we can find the average rate of change as follows:
 m = (y2-y1) / (x2-x1)
 m = (11-6) / (11-9)
 m = (5) / (2)
 m = 5/2
 Answer:
 the average rate of speed over the interval [9, 11] is: 
 D. 5 / 2

Answer 2

Answer:

Hence, option D is correct.

(i.e. Average speed is 5/2 miles/hour)

Step-by-step explanation:

We are asked to find the average rate of speed over the interval [9, 11].

We know that average speed is given as the ratio of total distance over total time.

the distance when time=9 hours is 6 miles.

and the distance when time=11 hours is 11 miles.

Hence, average speed is given as:

$Average speed=\dfrac{Total distance}{Total time}\\\\Average speed=\dfrac{11-6}{11-9}\\\\Average speed=\dfrac{5}{2}$

Hence average speed is 5/2 miles/hour.