Question

Suppose a 5-minute overseas call costs $5.91 and a 10-minute call costs $10.86. You also pay an initial fee for calling. The cost of the call and the length of the call are related What is the slope and what does it represent?

Answer 1

Let x represent the number of minutes and let y represent the cost of x minutes.

When x = 5, y = 5.91

When x = 10, y = 10.86

Slope, m = (x2 - x1)/(y2 - y1)

Slope = (10.86 - 5.91)/(10 - 5) = 4.95/5

Slope = 0.99

The slope represents the cost per minute of call made