A one lesson long maths problem devoted to answering this question.
Differentiated to 4 levels and including a further extension. For the easiest it leads learners through the problems step by step. Moving to the most difficult where they will have to research the costs and work out how to calculate the cost independently.
The extension task calls for students to present how and why their method works as well as consider how the problem changes if new ingredients are added.
Because I work in a Special School we have access to a kitchen so I have been able to link this with life skills work on preparing food and to vocational learning about setting up and running a cafe. We have also been able to make sandwiches which has been very motivational.
More problems like this to follow.
A little tweaking may be needed for learners who don’t eat bacon.