Final answer:
A maximum of 11 sandwiches can be made with 28 slices of bread and 11 slices of cheese, following a recipe that requires 2 slices of bread and 1 slice of cheese per sandwich, leaving 6 slices of bread unused.
Step-by-step explanation:
When provided with 28 slices of bread and 11 slices of cheese, and following the recipe that one sandwich consists of 2 slices of bread and 1 slice of cheese, you can make a maximum of 11 sandwiches because the amount of cheese slices determines the total number of sandwiches you can produce. After making 11 sandwiches, which would utilize 22 slices of bread (2 per sandwich) and all 11 slices of cheese, there will be 6 slices of bread left over.