Question

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 350 minutes and the cost
was $177.00. In July she used 900 minutes and the cost was $397.00.
A) Express the monthly cost C as a function of x, the number of minutes of calling time she used.
Answer: c(x) = 4x +
syntax error.
B) If Jane used 622 minutes of calling time in August, how much was her bill?
Answer: $

Answer 1

A) To express the monthly cost C as a function of x, we need to use the information given to find the fixed monthly fee and the charge per minute. We can set up a system of two equations to solve for these two values:

350m + f = 177 (where m is the charge per minute and f is the fixed monthly fee)
900m + f = 397

Solving this system of equations, we get:

m = 0.4
f = 37

Therefore, the monthly cost C as a function of x is:

C(x) = 0.4x + 37

B) If Jane used 622 minutes of calling time in August, we can use the function C(x) to find her bill:

C(622) = 0.4(622) + 37 = $274.80

Therefore, her bill for August would be $274.80.