a+b+c+d+e=30, a/2=b/3=c/4=d/5=e/6
b=3a/2, c=4a/2, d=5a/2, e=6a/2, inlocuim b c d si e in prima ecuatie
a+3a/2+4a/2+5a/2+6a/2=30, numitor comun 2
2a+3a+4a+5a+6a=60, 20a=60, a=60/20=3 ha
b=3*3/2=4,5 ha, c=4*3/2=6 ha, d=5*3/2=7,5 ha, e=6*3/2=9 ha
verificare : 3+4,5+6+7,5+9=30 ha