Fig. $2$ A control system block diagram

$[20$ pt$.]$ A control system block diagram is shown in Fig. $2.$

a$)$ Reduce the transfer function from $R$ to $C$ using block diagram algebra.

b$)$ Let $G_i(s)=\frac{i}{s+i}$ and $H_j(s)=\frac{1}{js+1}$ for $i=1,2,$dots,$5j=1,2,3.$ Using Matlab find the equivalent transfer function of the overall system