Answer:
a) $141.5 = 330m + b...... Equation 1
$337.5 = 890m + b..... Equation 2
b) $244.4
Explanation:
The phone company Splint has a monthly cellular plan where a customer pays a flat monthly fee and then a certain amount of money per minute used on the phone. If a customer uses 330 minutes, the monthly cost will be $141.5. If the customer uses 890 minutes, the monthly cost will be $337.5.
Required:
a. Find an equation in the form y= mx +b, where x is the number of monthly minutes used and y is the total monthly of the Splint plan.
If a customer uses 330 minutes, the monthly cost will be $141.5.
y = mx + b
$141.5 = 330m + b
If the customer uses 890 minutes, the monthly cost will be $337.5.
$337.5 = 890m + b
Combining the equations
$141.5 = 330m + b...... Equation 1
$337.5 = 890m + b..... Equation 2
b. Use your equation to find the total monthly cost if 624 minutes are used
Combining the equations
$141.5 = 330m + b...... Equation 1
$337.5 = 890m + b..... Equation 2
We Subtract Equation 2 from 1
-196 = -560m
m = -196/-560
m = 0.35
$337.5 = 890m + b..... Equation 2
$337.5 = 890 × 0.35 + b
$337.5 - 311.5 = b
b = 26
When x = 624
y = 624× m + b
m = 0.35 , b = 26
y = 624 × 0.35 + 26
y = 218.4 + 26
y = $ 244.4