MIN     X1 + X2 + X3 + X4 + X5 + X6 + X7
 SUBJECT TO          
 MON)  X1           + X4 + X5 + X6 + X7 >=   50
 TUE)  X1 + X2           + X5 + X6 + X7 >=   50
 WED)  X1 + X2 + X3           + X6 + X7 >=   50
 THU)  X1 + X2 + X3 + X4           + X7 >=   50
 FRI)  X1 + X2 + X3 + X4 + X5           >=   80
 SAT)       X2 + X3 + X4 + X5 + X6      >=   90
 SUN)            X3 + X4 + X5 + X6 + X7 >=   90
 END
 GIN 7