[tex]a=8-3\sqrt7+\dfrac12(9+6\sqrt7+7)[/tex]
[tex]a=8-3\sqrt7+\dfrac12(16+6\sqrt7)[/tex]
[tex]a=8-3\sqrt7+8+3\sqrt7=16[/tex]
[tex]m_a=\dfrac{a+b}{2}=\dfrac{16+24}{2}=20[/tex]
2)
x= numarul barbatilor
20x/100=x/5=nr. femeilor
x+x/5=120
6x=120·5
x=20·5=100 barbati
Femei= 100/5=20