\[\boxed{\mathbf{1038\ (1038).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[b_{1} + b_{2} + b_{3} =\]
\[= \frac{1}{8} \cdot \left( b_{4} + b_{5} + b_{6} \right)\]
\[8 \cdot \left( b_{1} + b_{1}q + b_{1}q^{2} \right) =\]
\[= b_{1}q^{3} + b_{1}q^{4} + b_{1}q^{5}\]
\[8b_{1} \cdot \left( 1 + q + q^{2} \right) =\]
\[= b_{1}q^{3}\left( 1 + q + q^{2} \right)\]
\[8b_{1} = b_{1}q^{3},\ \ q^{3} = 8,\]
\[\ \ q = 2\]
\[Ответ:q = 2.\]