[tex]a)M.aritm.pond.= \frac{2* \frac{1}{3}+3* \frac{1}{6} +4* \frac{3}{8} }{2+3+4} = \frac{ \frac{2}{3} + \frac{1}{2} + \frac{3}{2} }{9} = \frac{4+3+9}{54} = \frac{16}{54} = \frac{8}{27} [/tex]
[tex]b)M.aritm.pond.= \frac{3*0,5+4*1,12+5*3,2+8*4}{3+4+5+8} = \frac{1,5+4,48+16+32}{20} = \frac{53,98}{20} [/tex]