P V = ∑ i = 1 n R i ( 1 + r ) i , {\displaystyle PV=\sum _{i=1}^{n}{\frac {R_{i}}{(1+r)^{i}}},} where n is the number of years during which the capital will be productive, and Ri is the net return in year i; C k = ∑ i = 1 n R i ( 1 + M E C ) i , {\displaystyle C_{k}=\sum _{i=1}^{n}{\frac {R_{i}}{(1+MEC)^{i}}},} where Ck is the upfront capital outlays; this equation defines the MEC.