A phone company charges for service according to the formula: \( C = 15 + 0.04 n \) , where \( n \) is the number of minutes talked, and \( C \) is the monthly charge, in dollars. The slope in this equation is: \(\square\).
The slope's units are:
Minutes per Dollar
Dollars per Minute
The vertical intercept in this equation is \( ( y \) -coordinate value only): \(\square\).