Observam ca daca cuplezi termenii sumelor 2 cate 2 atunci o sa obtii 2 la fiecare termen
[tex]\frac{2}{5}+\frac{8}{5}=\frac{10}{5}=2[/tex]
[tex]\frac{3}{6}+\frac{9}{6}=\frac{12}{6}=2[/tex]
[tex]\frac{4}{7}+\frac{10}{7}=\frac{14}{5}=2[/tex]
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[tex]\frac{47}{50}+\frac{53}{50}=\frac{100}{50}=2[/tex]
exista 50-5+1=46 Astfel de cupluri, asadar daca le adunam
[tex]\frac{2}{5}+\frac{3}{6}+\frac{4}{7}+..+\frac{47}{50}+\frac{8}{5}+\frac{9}{6}+\frac{10}{7}+..+\frac{53}{50}=x+y=2*46[/tex]
Acum facel media aritmetica intre x si y
[tex]m_{a}=\frac{x+y}{2}=\frac{2*46}{2}=46[/tex]
