3b...........7z..........30kw
14 b.........7z.........30*7=210kw
14b..........1z..........210:7=30 kw
14b..........10 z............30*10=300 kw
2.700*115/100=805 lei (dupa marirea de 15 %)
805*110/100=885,5 lei (dupa a doua marire de 10%)
b) 700*x/100=885,5
x=885,5*100/700=126,5
Rezulta ca dupa o marire de 26,5 pretul va deveni 885,5
3. 25%........100 elevi
10%..........x elevi
x=10*100/25=1000/25=40 elevi