using JuMP
using HiGHS

y(x1,x2,x3)=400*x1+200*x2+250*x3
l(x1,x2,x3)=0.8*x1+0.2*x2+0.3*x3
w(x1,x2,x3)=3.0*x1+1.0*x2+1.5*x3
a(x1,x2,x3)=x1+x2+x3

model=Model(HiGHS.Optimizer)
@variable(model,x1>=0)
@variable(model,x2>=0)
@variable(model,x3>=0)
@objective(model,Max,y(x1,x2,x3))
@constraint(model,c1,l(x1,x2,x3)<=300)
@constraint(model,c2,w(x1,x2,x3)<=1000)
@constraint(model,c3,a(x1,x2,x3)<=625)
print(model)

optimize!(model)
objective_value(model)
myx1=value(x1)
myx2=value(x2)
myx3=value(x3)
myX=[myx1,myx2,myx3]
bookX=[187.5,437.5,0.0]
X(theta)=theta*myX+(1-theta)*bookX

X(1)
y(X(1)...)
X(0)
y(X(0)...)
X(0.5)
y(X(0.5)...)
X(0.25)
y(X(0.25)...)