\(\textbf{18 a)}\)
\begin{aligned}A=30,\, &B=25,\, C=40\\A:B:C&=30:25:40\\&=\frac{30}{5}:\frac{25}{5}:\frac{40}{5}\\&=6:5:8\end{aligned}
\(\textbf{18 b)}\)
\begin{aligned}\text{Total of} A,\,B,\,C&=30+25+40= \text{ 95 runs}\\A,B,C: \text{ Team}&= 19:36\\\therefore 19 \text{ parts}&=95 \text{ runs}\\1 \text{ part}&=95 \div 19\\&=5\\\text{Whole team}&= 36 \text{ parts}\\&=36\times 5 \text{ runs}\\&= 180\text{ runs}\end{aligned}
