Răspuns:
[tex]m = (\frac{1}{2} \times 8 + \frac{2}{3} \times 12 + \frac{3}{4} \times 16) \div 8 + 12 + 16[/tex]
[tex]m = (4 + 8 + 12) \div 36[/tex]
[tex]m = \frac{24}{36} [/tex]
[tex]m = \frac{2}{3} [/tex]
