notam cu r -nr de globuri rotunde
a-nr de globuri alungite
r+a=120
r:4+a:8=21 |·8 (inmultim toata ecuatia cu 8)
2r+a=168
r+a=120
---------- (scadem cele 2 ecuatii)
r / =48
a=120-48=72
verificare 48:4+72:8=12+9=21 cutii
raspuns:48 globuri rotunde si 72 globuri alungite