$($c$)$ Consider the seven$-$component system illustrated in the figure below. The reliabilities of

the components are as follows: $RA=0\mathrm{.}96,RB=0\mathrm{.}92,RC=0\mathrm{.}94,RD=0\mathrm{.}89,$

$RE=0\mathrm{.}95,RF=0\mathrm{.}88,RG=0\mathrm{.}90.$ Find the reliability of the system. If you had a choice of

improving system reliability by modifying any two components, how would you proceed?

$(10$ marks$)$