[tex]\dfrac{B}{4} + B = 30 \iff B + 4B = 120[/tex]
[tex]5B = 120 \implies B = 24[/tex]
=> sunt 24 băieți
c)
total punctaj: 2×4+2×5+4×6+6×7+11×8+3×9+2×10 = 219
număr elevi: 30
media clasei:
[tex]\dfrac{219}{30} = 7.3[/tex]
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simona2oo2
b) elevi = 30 nr fete = 25/100*b=1/4b nr fete + nr baieti = 30 1/4b+b=30 1/4b+4b/4=120/4 b+4b=120 5b=120 b=24 Si fete sunt 30-24=6 c) inmultesti nota cu numarul de elevi corespunzator si imparti la numarul de elevi total 4*2+5*2+6*4+7*6+8*11+9*3+10*2/2+2+4+6+11+3+2 = =8+10+24+42+88+27+20/30= =50+30+24+88+27/30= =80+112+27/30= =80+139/30= =219/30= =73/10= =7.3
Verified answer
Explicație pas cu pas:
b)
F + B = 30
F = 25%B = B/4
înlocuim:
[tex]\dfrac{B}{4} + B = 30 \iff B + 4B = 120[/tex]
[tex]5B = 120 \implies B = 24[/tex]
=> sunt 24 băieți
c)
total punctaj: 2×4+2×5+4×6+6×7+11×8+3×9+2×10 = 219
număr elevi: 30
media clasei:
[tex]\dfrac{219}{30} = 7.3[/tex]
nr fete = 25/100*b=1/4b
nr fete + nr baieti = 30
1/4b+b=30
1/4b+4b/4=120/4
b+4b=120
5b=120
b=24
Si fete sunt 30-24=6
c) inmultesti nota cu numarul de elevi corespunzator si imparti la numarul de elevi total
4*2+5*2+6*4+7*6+8*11+9*3+10*2/2+2+4+6+11+3+2 =
=8+10+24+42+88+27+20/30=
=50+30+24+88+27/30=
=80+112+27/30=
=80+139/30=
=219/30=
=73/10=
=7.3