Answer:
The cost is;
$18.43
Step-by-step explanation:
The general model for a linear equation is;
y = mx + b
let y be the monthly cost in dollars
x is the number of minutes
b will represent the base cost
m is the cost of the call per minute
so let us get m and b
Thus, we have;
18.25 = 31m + b
19.42 = 44m + b
Subtract i from ii
(19.42-18.25) = (44-31)m
1.17 = 13m
m = 1.17/13 = 0.09
To get b, we substitute the value of m in any of the equation
18.25 = 31 m + b
18.25 = 31(0.09) + b
b = 18.25 - 2.79
b = 15.46
so, the equation of the line is;
y = 0.09x + 15.46
Now to get the cost for 33 minutes
simply substitute the value of 33 for x
we have this as;
y = 0.09(33) + 15.46
y = $18.43
