Răspuns :
a+b+c=50
b+4=a
b+7=c
b+4+b+b+7=50
3b+11=50
3b=50-11
3b=39
b=13
a=13+4=17
c=13+7=20
b+4=a
b+7=c
b+4+b+b+7=50
3b+11=50
3b=50-11
3b=39
b=13
a=13+4=17
c=13+7=20
A+b+c=50
B+4=a
b+7=c
B+4 + b +b + 7=50
3b+11=50
3b=50-11
3b=39
b=39:3
b= 13
a= 13+4=17
c=13+7=20
acum proba
P:17+13+20=30+20=50
B+4=a
b+7=c
B+4 + b +b + 7=50
3b+11=50
3b=50-11
3b=39
b=39:3
b= 13
a= 13+4=17
c=13+7=20
acum proba
P:17+13+20=30+20=50