Răspuns :
a+b=300
b+c=500
a+c=400
2a+2b+2c=1200
2(a+b+c)=1200
a+b+c=1200:2=600
a+b=300
c=600-300
c=300
b+c=500
a=600-500
a=100
a+c=400
b=600-400
b=200
a+b=100+200=300
b+c=200+300=500
a+c=100+300=400
b+c=500
a+c=400
2a+2b+2c=1200
2(a+b+c)=1200
a+b+c=1200:2=600
a+b=300
c=600-300
c=300
b+c=500
a=600-500
a=100
a+c=400
b=600-400
b=200
a+b=100+200=300
b+c=200+300=500
a+c=100+300=400