Răspuns :
F+B=25 elevi
F+2=2·(B+3)
F+2+B+3=25+3+2=30 elevi
2·(B+3)+B+3=30 elevi
2·B+6+B+3=30 elevi
3·B+9=30 elevi
3·B=30-9=21 elevi
B=21:3=7 baieti
F=25-7=18 fete
F+2=2·(B+3)
F+2+B+3=25+3+2=30 elevi
2·(B+3)+B+3=30 elevi
2·B+6+B+3=30 elevi
3·B+9=30 elevi
3·B=30-9=21 elevi
B=21:3=7 baieti
F=25-7=18 fete
25+2+3=30 copii
|----| fete
|----|-----| baieti
30:3=10 fete
10*2=20 baieti
10-2=8 fete
20-3=17 baieti
|----| fete
|----|-----| baieti
30:3=10 fete
10*2=20 baieti
10-2=8 fete
20-3=17 baieti