The process for converting present values into future values is called compounding $>.$ This process requires knowledge of the values of three of

four time$-$value$-$of$-$money variables. Which of the following is not one of these variables?

The present value $($PV$)$ of the amount invested

The inflation rate indicating the change in average prices

The interest rate $($I$)$ that could be earned by invested funds

The duration of the investment $($ N $)$