The number of companies presenting cellular telephone service has grown rapidly in recent years. Plans they offer vary greatly and it can be diffcult to choose plan which is best for you. Here are two typical plans:
Plan 1: The flat fee of $50 per month for unlimited calls
Plan 2: The $30 per month fee for the total of 30 hours of calls and and extra charge of $0.01 per minute for all minutes over 30 hours
Create the mathematical model for each plan which provides total monthly cost in terms of total number of minutes of calls placed in a month.