Answer:
[tex]C=20+0.20N[/tex]
Step-by-step explanation:
Fixed monthly fee = $20
Amount charged per minute for long distance calls = $0.20
[tex]C[/tex] denotes total cost such that [tex]N[/tex] minutes are used for long distance calls.
Amount charged for [tex]N[/tex] minutes for long distance calls [tex]=0.20N[/tex]
Therefore, an equation for the total cost, C, when N minutes are used for long distance calls is [tex]C=20+0.20N[/tex]