\[\boxed{\mathbf{Страница}\mathbf{\ 31.}\mathbf{\ }\mathbf{Еуроки\ - \ ДЗ\ без\ мороки}}\]
\[\boxed{\mathbf{15.}}\]
\[\boxed{\mathbf{16.}}\]
\[450 - x = 60 \cdot 7\]
\[450 - x = 420\]
\[x = 450 - 420\]
\[x = 30.\]
\[480\ :x = 100\ :10\]
\[480\ :x = 10\]
\[x = 480\ :10\]
\[x = 48.\]
\[\boxed{\mathbf{17.}}\]
\[42\ :(18\ :6) =\]
\[= 14\ (посылок) - можно\ \]
\[перевязать.\]
\[Ответ:14\ посылок.\]