# Mengen
set I := { 1 to 2};  

# Variablen
var x[I] real >= 0;

# Zielfunktion
minimize cost: 40*x[1] + 60*x[2];

# Nebenbedingungen

subto naehrstoffA: 100*x[1] + 200*x[2] >= 90;

subto naehrstoffB: 80*x[1] + 150*x[2] >= 50;

subto naehrstoffC: 40*x[1] + 20*x[2] >= 20;

subto naehrstoffD: 10*x[1]  >= 2;

subto all: sum <i> in I: x[i] <= 1;