I'm new to solver and am trying to add a constraint where, when I'm selling two items (X and Y), at least 60% of those items must be item X. I tried making the constraint as X >= .6(X+Y).

When I do that, solver treats it as if qty X must be exactly 60% rather than at least 60%, so I get an output of 6 X and 4Y. (With my other constraints, the optimal answer should be 13X and 8Y).

I tried making a ratio of 1.5 but I get a DIV/ZERO error when I try to set that up.

Any help would be tremendously appreciated.

Thanks!

Product Mix - Solver.xlsx