Media notelor ultimilor 15 elevi = 7,55
Media aritmetica a clasei = 7,25 = suma notelor celor 25 elevi/25
Media aritmetica a clasei se calculeaza impartind suma tuturor notelor la numarul elevilor.
Media primilor 10 = 6,80 = suma notelor primilor 10/10
1) suma notelor celor 25 elevi = 7,25 x 25 = 181,25
2)suma notelor primilor 10 elevi = 6,8 x 10 = 68
3)suma notelor celorlalti 15 elevi = 181,25-68 = 113,25
4)media notelor ultimilor 15 elevi = 113,25:15 = 7,55