Suppose you use "m" minutes in a month and each minute is $0.05, so your minute bill would be:
0.05 * m
Per month, there is a fixed rate of $15 , no matter how many minutes you use.
So, that's a fixed cost.
Total monthly charge would be:
15 + 0.05m
The cost, c, is:
[tex]c=0.05m+15[/tex]Correct Answer Choice is Option B
