Answer:
The equation is given below as

The general equation of a line is given below as

The graph represents the equation of cost in dollars against minutes
By comparing the coefficient, we will have the slope of the equation to be

Hence,
The slope of the equation is = 0.04
The slope's units is dollars per minute
The vertical intercept of the equation is the point when the value of n=0

Hence,
The vertical intercept in this equation = 30