The dual is $\boxed{D:\ \min b^Ty\text{ subject to }A^Ty\ge c,\ y\ge0}$. For feasible points $c^Tx\le y^TAx\le y^Tb$, so its feasible objectives bound the primal objective from above. This is <weak duality> with the given maximization convention.

Solution

Past exam of the Probability, statistics and options II course of the University of Oxford / 2009 / T / T2 / a / i / Solution

 Solution (source code)