Răspuns:
n = 3
Explicație pas cu pas:
[tex](\frac{2}{5} )^{n} : \frac{4}{5} = \frac{2}{25}[/tex]
[tex](\frac{2}{5} )^{n} = \frac{2}{25} *\frac{4}{5}[/tex]
[tex](\frac{2}{5} )^{2} = \frac{8}{125}[/tex]
[tex](\frac{2}{5} )^{n} = (\frac{2}{5} )^{3}[/tex]
[tex]n = 3[/tex]