a-primul copil
b-al doilea
c-al treilea
a+b+c=216
a=3(b+c)
c=b+20
a=6b+60
6b+60+b+b+20=216
8b=136
b=17
a=6.17+60=156
c=17+20=37
2.(a+b+c)/3=17
a+b+c=51
c=15
2a=b-3⇒b=2a+3
a+2a+3+15=51
3a=51-18=33
a=11
b=2.11=3=25
c=15
3.a-b=157
a/b=5 rest 17⇒a=5b+17
5b+17-b=157
4b=157-17=140
b=35
a=5.35+17=192