Question

1.Calculati media aritmetica a urmatoarelor numere rationale: 0,4 ; 0,75
2.Calculati media aritmetica ponderata a numerelor rationale 1,25 si 0,8(3) cu ponderile 2,respectiv 3

Answer 1

     
$1) \\ m_a = \frac{0,4+0,75}{2}= \frac{1,15}{2}=\boxed{0,575} \\ \\ 2) \\ m_{ap}= \frac{1,25\;\cdot\;2+0,8(3)\;\cdot\;3}{2+3}= \frac{1,25\;\cdot\;2+\frac{83-8}{90} \;\cdot\;3}{2+3}= \\ \\ = \frac{1,25\;\cdot\;2+\frac{75}{90} \;\cdot\;3}{5}= \frac{1,25\;\cdot\;2+\frac{25}{30} \;\cdot\;3}{5}= \\ \\ =\frac{1,25\;\cdot\;2+\frac{25}{10}}{5}=\frac{2,5+2,5}{5}=\frac{5}{5}=\boxed{1}$

Answer 2

1)
ma=(0,4+0,75):2=1,15:2=0,575
2)
1,25=125:100=25:20=5:4
0,8(3)=(83-8):90=75:90=15:18=5:6
mp=(5/4x2+5/6x3):(2:3)=(5:2+5:2):5=(10:2):5=5:5=1