Which of the following would be a reasonable approximation for the length of time it would take this person to run 6 miles?

The correct answer is: ≅ 66 min

A linear function is of the form y = mx + b where 'm' and 'b' are real numbers.  A linear function represents a line, i.e., its graph is a line. Here,

• 'm' is the slope of the line
• 'b' is the y-intercept of the line
• 'x' is the independent variable
• 'y' (or f(x)) is the dependent variable

Take any points from the graph
(x1, y1) = (2, 20) and (x₂, y₂) = (5, 55).
Step 1: Find the slope of the function using the slope formula:
m = (y₂ - y1) / (x₂ - x1) = (55 - 20) / (5 - 2) = 35/3
Step 2: Find the equation of linear function using the point slope form.
y - y1 = m (x - x1)
y - 20 = 35/3 (x - 2)
y - 20 = 35/3 (x - 2)
y  = 35/3(x) - 10/3
for x = 6
y  66
Thus, a reasonable approximation for the length of time it would take this person to run 6 miles is 66minutes.