A banker has a retirement portfolio that increases at a particular rate per year. The total amount, in dollars, in the portfolio can be modeled by the equation. y = p (1 + q )x What is the meaning of the parameter p in this model? It is the amount in the portfolio after x years. It is the initial amount in the portfolio. It is the number of years the banker has had the portfolio. It is the rate of change for the portfolio per year.