Question

The phone company NextFell 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 260 minutes, the monthly cost will be $114. If the customer uses 640 minutes, the monthly cost will be $247.
A) Find an equation in the form y= mx+b, where x is the number of monthly minutes used y is the total monthly cost of the NextFell plan.


Answer: _____



B) Use your equation to find the total monthly cost if 949 minutes are used.


Answer: If 949 minutes are used, the total cost will be _____ dollars.

Answer 1

Answer:

Explained below.

Step-by-step explanation:

(A)

Use two-point form to determine the equation for the total monthly cost of the NextFell plan.

$(y-y_{1})=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}\cdot (x -x_{1})\\\\(y-247)=\frac{247-114}{640-260}\cdot (x-640)\\\\(y-247)=0.35x-224\\\\y=0.35x+23$

(B)

Compute the total monthly cost if 949 minutes are used as follows:

$y=0.35x+23\\\\=(0.35\times 949)+23\\\\=355.15$

Thus. the total monthly cost if 949 minutes are used is $355.15.