/* Objective function */
min: 24 x1 + 20 x2 + 30 x3 ;

/* Variable bounds */
0.1 x1 + 0.2 x2 + 0.3 x3 >= 0.2;
0.18 x1 + 0.09 x2 + 0.45 x3 >= 0.2;
 x1+ x2 + x3 = 1;