The graph is missing, so i have attached it.
Answer:
$0.40 per minute
Explanation:
From the attached graph, we can see that it is a linear graph.
Thus, to find the unit rate paid by Ken, we will calculate the slope by picking two coordinate points with thick dots on the blue and calculating it.
Point 1 = (15, 6)
Point 2 = (35, 14)
Slope = (y2 - y1)/(x2 - x1)
Slope = (14 - 6)/(35 - 15)
Slope = 8/20
Slope = $0.40 per minute