30. For which values of $b$, the system of inequalities
$$
\left\{\begin{array}{l}
0.5(2 x+5)<2(x-2)+5 \\
2(b x-1)<3
\end{array}\right.
$$

has no solution?
(Answer: $b \in\left[\frac{5}{3},+\infty\right)$ )