Question

Media aritmetica a 3 nr.rationale = cu 6,8 si media aritmetica a primelor 2 nr. = cu 4 intregi si 1/2.
Aflati al treilea numar.

Answer 1

Notam numerele cu a , b si c ! => $\frac{a+b}{2} =4 \frac{1}{2} = \frac{9}{2} =\ \textgreater \ \frac{a+b}{2} = \frac{9}{2} =\ \textgreater \ a+b = \frac{2*9}{2} \\ =\ \textgreater \ a+b=9 \\ \frac{a+b+c}{2} =6,8=\ \textgreater \ a+b+c =2*6,8=\ \textgreater \ a+b+c=13,6 \\ =\ \textgreater \ 9+c=13,6=\ \textgreater \ c=13,6-9=\ \textgreater \ c=4,6$