\[\boxed{\mathbf{834\ (834).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[c_{18} = c_{12} \cdot q^{6},\ \ c_{36} = c_{12} \cdot q^{24},\]
\[\text{\ \ }c_{50} = c_{12} \cdot q^{38}\]
\[\boxed{\mathbf{834.\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\frac{96}{120} \cdot 100\% = 80\%.\]
\[Ответ:80\%.\]