2m+12s=1300
2m+16s=1600/2
M+8s=800
M=800-8s
2(800-8s)+12s=1300
1600-16s+12s=1300
1600-4s=1300
1600-1300=4s
S=300:4
S=75 lei costa un scaun
M=800-8x75
M=800-600
M=200 lei costa o masa
Verificare
2x200+12x75=1300
400+900=1300
1300=1300
2x200+16x75=1600
400+1200=1600
1600=1600