Răspuns :
se ia prin incercare
1+2+3+4 = 10 CORECT
2+3+4+5 = 14 CORECT
3+4+5+6 = 18 CORECT
4+5+6+7 = 22>20 Gresit
1+2+3+4 = 10 CORECT
2+3+4+5 = 14 CORECT
3+4+5+6 = 18 CORECT
4+5+6+7 = 22>20 Gresit