Just polishing up my revision for tomorrow, given the question -

''The forestry section of a country estate makes two types of wooden fences that it sells to a garden centre for fixed prices. Each panel fence, for which the estate receives£40, requires 48 feet of wood and one hour of labour to make. Each trellis fence, for which the estate receives £20, requires 30 feet of wood and ¾ hour of labour to make. The estate has available 8400 feet of wood and 190 hours of labour.''

I can do all the graphwork and calculate maximum revenue, but then i have to -

''Write down the dual of this problem and use the complementary slackness relationships to deduce its solution.''

I understand it as the minimum value? However given the data im not sure how to calculate this and my notes seem to indicate some form of matrix algebra is necessary