\[Стр.\ 14.\]
\[\boxed{\mathbf{14.}}\]
\[\boxed{\mathbf{15.}}\]
\[x\ :53\frac{1}{3} = 22,5\ :280\]
\[280x = 22,5 \cdot 53\frac{1}{3}\]
\[280x = \frac{225 \cdot 160}{10 \cdot 3}\]
\[280x = 1200\]
\[x = 1200\ :280 = \frac{1200}{280} = \frac{30}{7} =\]
\[= 4\frac{2}{7}\]
\[Ответ:4\frac{2}{7}.\]
\[\boxed{\mathbf{16.}}\]
\[4,86 \cdot a = b \cdot 5,4\]
\[\frac{a}{b} = \frac{5,4}{4,86}\]
\[\frac{a}{b} = \frac{54 \cdot 100}{10 \cdot 486}\]
\[\frac{a}{b} = \frac{10}{9};\]
\[Ответ:10\ :9.\]