Răspuns :
a) 28 de elevi
b) 5 elevi
c)(2·10+3·9+2·8+6·7+5·6+3·5+2·4)/(2+3+2+6+5+3+2)
=(20+27+16+42+30+15+8)/23
b) 5 elevi
c)(2·10+3·9+2·8+6·7+5·6+3·5+2·4)/(2+3+2+6+5+3+2)
=(20+27+16+42+30+15+8)/23