Making Marx’s Surplus Equation Work (Within Sraffa’s Standard System)

In this article, a solution is proposed to the problem of making Marx’s Surplus equation work correctly, by using a version of it adapted to modern economics. In the end, the rate of profit in the economic system results to be ruled by labour exploitation and organic composition of capital, just as Marx had supposed, but this happens through ratios which only refer to Sraffa’s Standard System, not the whole economy.