\[\boxed{\text{995\ (995).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[b_{5} = 1\frac{1}{2} = \frac{3}{2},\ \ q = - \frac{1}{2},\ \ \]
\[S_{5} = ?\]
\[b_{5} = b_{1} \cdot q^{4} = \frac{3}{2},\]
\[b_{1} = \frac{b_{5}}{q^{4}} = \frac{3}{2} \cdot 2^{4} = 24,\]
\[S_{5} = b_{1} \cdot \frac{q^{5} - 1}{q - 1} = 24 \cdot \frac{\frac{1}{32} - 1\ }{- \frac{1}{2} - 1} =\]
\[= 24 \cdot \left( - \frac{33}{32} \right) \cdot \left( - \frac{2}{3} \right) = \frac{33}{2} =\]
\[= 16,5.\]