prima scoala= 30% ; reztul este 70%
a doua scoala= 50/100* 70/100= 35/100=35%
a treia scoala= 30/100 *x+ 135
30x /100 + 35x/100+30x/100+135 = x
95x+13500= 100x
5x= 13500 |÷5
x= 2700
Prima scoala : 30/100* 2700= 810
A doua scoala: 35/100*2700= 945
A treia scoala: 810+135= 945
810+945+945= 2700 elevi