[tex]\displaystyle
n = \text{numarul cautat} \\ \\
1) \\ \\
\frac{2}{5}\times n= 36 \\ \\
n=36:\frac{2}{5}=36\times \frac{5}{2} = \frac{36 \times 5}{2} = 18 \times 5 = \boxed{90} \\ \\ 2) \\ \\
\frac{7}{5}\times n= 280 \\ \\
n=280:\frac{7}{5}=280 \times \frac{5}{7} = \frac{280 \times 5}{7} = 40 \times 5 = \boxed{200}[/tex]
