1)To calculate ROI, the benefit (or return) of an investment is divided by the cost of the investment, and the result is expressed as a percentage or a ratio. The returnon investment formula: In the above formula, "Gain from Investment” refers to the proceeds obtained from the sale of the investment of interest.
3)In classical economics rent was the return to an "owner" of land. In later economic theory this term is expanded as economic rent to include other forms of unearned income typically realized from barriers to entry. Land ownership is considered to be a barrier to entry because land owners make no contribution to the production process. They simply prevent others from using that which would otherwise be useful.
