Question 32 examined planning with limiting factors, firstly in a single limiting factor situation, then using linear programming in a multiple limiting factor situation.

The final part of the question moved on to linear programming with multiple limiting factors.

This is generally a popular topic and this was overall well answered.

Many candidates attempted this part of the question before any other part of Section C – good examination technique especially when under time pressure.

What this question demonstrated well was that most candidates are comfortable with the steps involved in linear programming; however there is a lack of in depth understanding of how it works.

For example virtually all candidates could identify the iso-contribution line and feasible region when given on a graph, but few could explain what they meant.

Many explained what they were for (finding the optimum point), but not that the iso-contribution line shows all points giving the same contribution, or that the feasible region shows all possible production plans that meet all of the constraints.

Similarly, most could define slack in the context of scarce resources, but found it harder to identify slack variables from a completed graph.