Question $6(10$ points$)$

Reter to the figure below; determine the overall network reliability given the nochal reliabilities of the following subsystems are. Type out your answer in tout

$Ra=0\mathrm{.}9,Rb=0\mathrm{.}8,Rc=0\mathrm{.}7,Rd=0\mathrm{.}8,Re=0\mathrm{.}9,Rf=0\mathrm{.}5$

Formulas: $R(t)=1-F(t)$Rpair$=$Ra$+$Rb$-($Ra$)(Rb)$; Rparallel $=1-(1-R{)}^n$; Rparallel $=1-(1-Ra)(1-Rb)(1-Rc)$