Answer:
$ 15.97
Step-by-step explanation:
Being a linear function, we can calculate the equation that determines this function in the following way:
y = m * x + b
let m be the slope and b the independent term or intercept.
We have two points: (41, 14.17); (95, 19.03)
Now the slope is equal to:
m = (y2 - y1) / (x2 - x1)
replacing
m = (19.03 - 14.17) / (95 -41)
m = 0.09
now the intercept can be calculated like this:
y = m * x + b; solve for "b":
b = y - m * x
replacing with the data of the first point (41, 14.17)
b = 14.17 - 0.09 * 41
b = 10.48
Therefore the function is as follows:
cost = 0.09 * (minutes) + 10.48
We are told that how much is the cost in 61 minutes in call, we only replace:
cost = 0.09 * (95) + 10.48
cost = 15.97
Which means that in 61 minutes of calling the monthly cost is $ 15.97
