\[\boxed{\mathbf{521\ (521).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\left. \ \begin{matrix} Иван - 23\%\ яблок \\ Петр - 39\%\ яблок \\ Федор - 190\ кг\ \ \ \ \ \ \ \\ \end{matrix} \right\}\ ?кг\]
Решение.
\[1)\ 100 - (23 + 39) =\]
\[= 100 - 62 = 38\% - яблок\ \]
\[собрал\ Федор.\]
\[2)\ 38\% = \frac{38}{100} = \frac{19}{50}\]
\[Ответ:500\ кг\ яблок.\]
\[\boxed{\mathbf{521.}\mathbf{\ }}\]
\[\frac{24}{25}\ :\frac{2}{5} = \frac{24}{25} \cdot \frac{5}{2} = \frac{12}{5}\]
\[\frac{12}{5}\ :6 = \frac{12}{5} \cdot \frac{1}{6} = \frac{2}{5}\]
\[\frac{2^{\backslash 3}}{5} - \frac{1^{\backslash 5}}{3} = \frac{6}{15} - \frac{5}{15} = \frac{1}{15}\]
\[\frac{1}{15}\ :\frac{1}{5} = \frac{1}{15} \cdot 5 = \frac{1}{3}\]
\[\frac{1}{3} + \frac{1}{6} = \frac{2}{6} + \frac{1}{6} = \frac{3}{6} = \frac{1}{2}\]