Răspuns :
p=30clase
et.1=p+50clase
et.2=p+et.1
et.1=30+50=80clase
et.2=30+80=110clase
30+80+110=220clase in scoala
et.1=p+50clase
et.2=p+et.1
et.1=30+50=80clase
et.2=30+80=110clase
30+80+110=220clase in scoala