Surplus definition and example (linear programming)

In general, resources will be limited and therefore there will be a maximum available.

The relevance of a minimum is most likely (as in this question) where a contract has been signed and therefore there is a minimum production that must be achieved.

In the question that you are asking about, there are contracts and therefore they must produce at least 1,200 laundry and 2,000 dry cleaning.

The optimal solution is to produce 1,200 laundry and 9.600 dry cleaning. For laundry, the constraint was binding – they would have produced less than 1,200 if they could have. For dry cleaning it was not binding – it was the other constraints that limited them to 9,600. 9,600 is far more than the minimum of 1,200 that they are required to produce and therefore there is ‘surplus’.

(Obviously the word ‘produce’ is not quite the right word here, but it should be obvious what I mean.)

Have you watched the free lectures? (because if you did then you would not need the text books – the lectures are a complete classroom course 🙂 )

Suppose there was a constraint that you had to use at least 1,000 kg of material.
Suppose that at the optimum solution you were actually using 1,200 kg of material.
Then we would say that there was surplus of 200 kg.

(Surplus’s like this are rare because usually constraints say that you cannot use more than (say) 1000 kg rather than saying that you cannot use less than 1000 kg)

You are welcome 🙂