(10+20+30)%.................24 e.
60%.......................24e
100%.......................x
x=24*100 /60= 40 e. = total elevi.
nota5: 10/100*40= 4 e
nota6: 10/100*40=4 e
nota7: 20/100*40= 8 e
nota8: 30/100*40= 12 e.
nota9: 20/100*40= 8 e
nota10:10/100*40= 4 e
M= (4*5+ 4*6+8*7+12*8+8*9+4*10)÷ 40= 308÷40= 7, 7