A mathematical model for population growth over short intervals is given by P = Poet, where Po is the population at time t= 0, r is the continuous compound rate of growth, t is the time in years, and P is the population at time t. How long will it take a country's population to quadruple if it continues to grow at its current continuous compound rate of 0.59% per year? Substitute the given values into the equation for the population. Express the population at time t as a function of Po. Po = Poel (Simplify your answers.) The population will quadruple in about years . (Type an integer or decimal rounded to one decimal place as needed.)