A mathematical model for population growth over short intervals is given by PequalsUpper P 0 e Superscript rt​, where Upper P 0 is the population at time tequals​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 triple if it continues to grow at its current continuous compound rate of 0.86​% per​ year?