Hello,
I was able to do this in 15 very easily, and that file is attached. However, I was unable to get the routine to work in Prime (unsurprisingly). As my university has removed the old mathcad program (and it will be dropped from support before long according to PTC) I was trying to atleast understand how to get the answer in Prime.
I'm afraid the way in my earlier post of using a programming block didn't work as expected, and thus I'm unsure how to be able to get the maximum or minimum of an objective function in terms of varying parameters WITH constraints given that can over define the problem.