Răspuns :
a+b+c=69
a+b=21 -> c=69-21
c=48
a+c=59
a+48=59
a=59-48
a=11
b+c=58
b+48=58
b=58-48
b=10
proba:
11+10+48=69
a+b=21 -> c=69-21
c=48
a+c=59
a+48=59
a=59-48
a=11
b+c=58
b+48=58
b=58-48
b=10
proba:
11+10+48=69