I2.3 Dividing $\$(3000+b)$ in a ratio $5: 6: 8$, the smallest part is $\$ c$. Find $c$.
$\begin{array}{l}\text { Sum of money }=\$(3000-2620)=\$ 380 \\ c=\frac{5}{5+6+8} \cdot 380=\frac{5}{19} \cdot 380=100\end{array}$