Question

A pre-paid cell phone company charges $19.65 as a monthly access fee and $0.09 per minute of calling time.

Express the monthly cost c
in terms of minutes of call time.


What will the monthly cost be if you make 435 minutes of calls this month?

Answer 1

To express the monthly cost \( c \) in terms of the number of minutes of call time \( m \), we can set up the equation:

\[
c = 19.65 + 0.09m
\]

where:
- \( 19.65 \) is the monthly access fee,
- \( 0.09m \) is the cost for \( m \) minutes of calling time at $0.09 per minute.

Now, to find the monthly cost if you make 435 minutes of calls, we can substitute \( m = 435 \) into the equation:

\[
c = 19.65 + 0.09 \times 435
\]

Calculating \( 0.09 \times 435 \):

\[
0.09 \times 435 = 39.15
\]

Now, substituting this back into the equation for \( c \):

\[
c = 19.65 + 39.15 = 58.80
\]

Therefore, if you make 435 minutes of calls this month, the monthly cost will be \( \mathbf{58.80} \).