[tex]a)[/tex]
[tex] \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{ \frac{4+3+9}{6}}{9}= \frac{ \frac{16}{6} }{9} = \frac{8}{3*9}= \frac{8}{27} [/tex]
[tex]b)[/tex]
[tex] \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}=2,699 [/tex]
