Question

Ava wants to figure out the average speed she is driving. She starts checking her car’s clock at mile marker 0. It takes her 4 minutes to reach mile marker 3. When she reaches mile marker 6, she notes that 8 minutes total have passed since mile marker 0.
What is the average speed of the car?
a. 0.40
b. 0.75
c. 1.33
d. 2.75

What is an equation of the line that represents n, the number of mile marker passed, as a function of t, time in minutes?
a. n-4= 0.4(t-3)
b. n-6= 0.75(t-8)
c. n+3= 1.33(t+4)
d. n+8= 2.5(t+6)

Answer 1

The average speed is obtained by finding the slope of the function in the given interval:

$v =\frac{y2-y1}{x2-x1}$

Substituting values we have:

$v =\frac{6-3}{8-4}$

Rewriting:

$v =\frac{3}{4}$

$v = 0.75$

Then, the generic equation of the line is:

 $n-n0 = v (t-t0)$

Where,

v: average speed (slope of the line)

(t0, n0): ordered pair that belongs to the line.

Substituting values we have:

 $n-6 = 0.75 (t-8)$

Answer:

the average speed of the car is:

b. 0.75

an equation of the line is:

b. n-6= 0.75(t-8)

Answer 2

Speed is 0.75

Equation is n-6= 0.75(t-8)