SOLUTION: Jane has a pre-paid cell phone with Splint. She can't remember the exact costs, but her plan has a monthly fee and a charge for each minute of calling time. In June she used 130 mi

Algebra.Com
Question 1200356: Jane has a pre-paid cell phone with Splint. She can't remember the exact costs, but her plan has a monthly fee and a charge for each minute of calling time. In June she used 130 minutes and the cost was $76.50. In July she used 510 minutes and the cost was $209.50.
A) Express the monthly cost as C as a function of X, the number of minutes of calling time she used.
Answer:

B) If Jane used 205 minutes of calling time in August, how much was her bill?
Answer: $
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39617)   (Show Source): You can put this solution on YOUR website!
"Splint" cell phone plan? A repeat question from several days ago?

Look for points, (x,y) for x minutes, y cost.
(130, 76.5) and (510, 209.5) They are on a line. You know what to do.
Answer by ikleyn(52786)   (Show Source): You can put this solution on YOUR website!
.
Jane has a pre-paid cell phone with Splint. She can't remember the exact costs, but her plan has a monthly fee
and a charge for each minute of calling time.
In June she used 130 minutes and the cost was $76.50.
In July she used 510 minutes and the cost was $209.50.
A) Express the monthly cost as C as a function of X, the number of minutes of calling time she used.
B) If Jane used 205 minutes of calling time in August, how much was her bill?
~~~~~~~~~~~~~~~~~~~~~~~ 

The difference in the cost, 209.50 - 76.50 = 133 dollars, is due to the difference of minutes

    510 - 130 = 380 minutes.


Hence, each minute costs   = 0.35 dollars.


Now we can compute the monthly fee.  It is  76.50 - 130*0.35 = 31.00  dollars,
from the June's bill.


Hence, the cost function is  C(X) = 31 + 0.35*X.


It is your ANSWER to question (A).


To answer question (B), you should calculate

    C(205) = 31 + 0.35*205 = 102.75 dollars.


It is the ANSWER  to question (B).

Solved.



RELATED QUESTIONS

The phone company Splint has a monthly cellular plan where a customer pays a flat monthly (answered by ikleyn,josgarithmetic)
Amber is signing up for cell phone service. She is trying to decide between Plan A,... (answered by jojo14344)
The phone company, Splint, has a monthly cellular plan where the customer pays a flat... (answered by ikleyn)
How do you solve a linear equation when the constant isn't given? For example: Lisa can... (answered by josmiceli)
The phone company Splint has a monthly cellular plan where a customer pays a flat monthly (answered by stanbon)
Customers of a phone company can choose between two service plans for long distance... (answered by rwm)
Customers of a phone company can choose between two service plans for long distance... (answered by drcole)
Customers of a phone company can choose between two service plans for long distance... (answered by fractalier)
Customers of a phone company can choose between two service plans for long distance... (answered by josmiceli)