In This article, A refers back to the long run value of the expense; P refers to the principal sum to generally be invested; r refers to the rate of interest; n refers to the volume of periods the interest receives compounded each year; t refers back to the tenure https://www.google.com/maps/d/u/0/viewer?mid=1o3vHoDG_5EIkMXyD_8nuLLiHqxZbkJg