\[b_{n} = 3n - 1\]
\[b_{1} = 3 - 1 = 2;\]
\[b_{30} = 90 - 1 = 89.\]
\[S_{30} = \frac{b_{1} + b_{30}}{2} \cdot 30 = 15 \cdot (2 + 89) =\]
\[= 15 \cdot 91 = 1365.\]
\[Ответ:1365.\]