I have five additives that can be mixed into a chemical. Each one can be mixed in at a discrete percentage from 0.02% to 0.22% of the chemical (i.e. 0.02%, 0.03%, 0.04%,...0.22%). Each additive must be present, so mixed in at least 0.02%. The restriction is that the sum of all percentages cannot exceed 0.3%, but the sum can be less than that, so long as each additive is present. Without the restriction the answer is easy. But I can't figure out how to eliminate the number of combinations that would exceed the maximum allowed. If one additive is mixed at 0.22%, then the other four must be 0.02% each and only that.