28)90xN/100=243 rezulta N=100x243/90=270 elevi clasa VIII
18xE/100=270 rezulta E=100x270/18=1500 elevi ai scolii
29) S-suma depusa
Dobanda 15S/100
Suma retrasa S+15S/100=115S/100
115S/100=690, S=690x100/115=600 lei
30)6x100/24=25%
31)8x100/10=80%
32) sa-a majorat cu 28-25=3 lei
3x100/25=12%
33)nu a rezolvat 10-8=2 probleme
2x100/10=20%