\[6\frac{5}{9} \cdot (n - 9) + 2\frac{2}{9} \cdot (18 - n) =\]
\[= 6\frac{5}{9}n - \frac{59 \cdot 9}{9 \cdot 1} + \frac{20 \cdot 18}{9 \cdot 1} - 2\frac{2}{9}n =\]
\[= \left( 6\frac{5}{9} - 2\frac{2}{9} \right)n - 59 + 40 =\]
\[= 4\frac{3}{9}n - 19 = 4\frac{1}{3}n - 19\]
\[n = 0,3:\]
\[4\frac{1}{3}n - 19 =\]
\[= 4\frac{1}{3} \cdot 0,3 - 19 = \frac{13 \cdot 3}{3 \cdot 10} - 19 =\]
\[= \frac{13}{10} - 19 = 1,3 - 19 = - 17,7.\]