Final answer:
The value of the C-intercept in this scenario represents the cost of a call when it lasts for zero minutes. By finding the slope of the line and using the slope-intercept form, we can determine the value of the C-intercept. In this case, the C-intercept is $0.12.
Step-by-step explanation:
The C-intercept in this scenario represents the cost of a call when it lasts for zero minutes. To find the value of the C-intercept, we need to determine the cost of a call when it lasts for zero minutes. From the given information, we can see that a 10-minute call costs $1.20, a 15-minute call costs $1.80, and a 20-minute call costs $2.40.
If we assume that the relationship between the cost of the call and the duration of the call is linear, we can find the slope of the line using the formula m = ΔC / ΔX, where ΔC is the change in cost and ΔX is the change in duration. In this case, ΔC = $2.40 - $1.20 = $1.20 and ΔX = 20 - 10 = 10.
Therefore, the slope of the line is m = $1.20 / 10 = $0.12. The equation of the line can be written as C = mx + b, where C is the cost of the call, x is the duration of the call, m is the slope, and b is the y-intercept. Substituting the values, we have C = $0.12x + b.
Since the C-intercept represents the cost of a call when it lasts for zero minutes, we can substitute x = 0 in the equation and solve for b. C = $0.12(0) + b, which simplifies to C = b. Therefore, the value of the C-intercept is $0.12.