Express the capacity constraints in terms of the number of hours available to produce these two products each month and the total number of hours needed to produce the number of items from each product we plan to produce during that month. We expressed capacity constraint in terms of the number of items we plan to produce and the number of items we can produce (our capacity allows us).

Excel does not accept this model as a linear one. So, we need to use the GRG optimization algorithm instead of Simplex.