Does this work for you
Manipulate[ NMaximize[{(*Objective function*)-6p+92t, (*Constraints*)-0.3p+12t>=(w-11.81)&&-4p+34t>=x-228.92&& -3p+133t==y-163.28&&6p-92t>=z-128.69&&p>=0&&t>=0},{p,t}], {w,6,16},{x,170,200},{y,150,300},{z,50,200}]
Dear Mr. Bill, Thanks for your prompt reply. It works fine. There was additional square brackets in my code after the manipulate. Kind Regards.
