Question

Calculati media aritmetica ponderata a numerelor:
a)1 pe 3;1 pe 6;3 pe 8 cu ponderile 2;3 si respectiv 4

Answer 1

(1/3 *2+6/3*3+ 3/8*4)/(2+3+4)=
=(2/3+6+3/2)/9=
=(4+36+9)/54=
=49/54=0,9(074)

Answer 2

$\displaystyle \frac{ 2 \cdot \frac{1}{3} +3 \cdot \frac{1}{6} +4 \cdot \frac{3}{8} }{2+3+4} = \frac{ \frac{2}{3} + \frac{3}{6} + \frac{12}{8} }{9} = \frac{ \frac{2}{3} + \frac{3}{6} + \frac{3}{2} }{9} = \frac{ \frac{4}{6} + \frac{3}{6} + \frac{9}{6} }{9} = \\ \\ = \frac{ \frac{16}{6} }{9} = \frac{16}{6} :9= \frac{16}{6} \cdot \frac{1}{9} = \frac{16}{54} = \frac{8}{27}$