This work makes a methodological proposal on how to measure a just remuneration rate for work on the basis of its marginal contribution to product value. It is applied to the production of tangible goods and comes from a linear programming model whose dual function stipulates the shadow prices that indicate the marginal contribution of the value produced of each factor involved in production. It is a novel approach given that in marginalist work no approach exists ex profeso on the subjects of exploitation rate and the remuneration rate for work. It also presents an interesting approach on the subject of opportunity prices with the substitution of productive factors based on the degree of intensity used in production, as well as its contribution to the value produced. It is shown that even within a utilitarian thesis the theme of exploitation is applicable. Theorists of this view evade the subject by attempting to establish an exposition of the economic problem from a scientific and positivist viewpoint without implications of a political-normative kind.