Consider a product consisting of four components $($A$,$ B$,$ C & D$),$ each of which has to work in order for the product to function properly. Reliability for each component is given as follows.

$R(A)=0\mathrm{.}91$

$R(B)=0\mathrm{.}82$

$R(C)=0\mathrm{.}95$

$R(D)=0\mathrm{.}99$

$0\mathrm{.}5362$

$0\mathrm{.}2345$

$0\mathrm{.}7018$

$0\mathrm{.}5000$