Eddie Tererai Mhishi

probability of a system being up in series = p1*p2*...pn probability of a system being up in parallel=1 -((1-p1)*(1-p2)*..(1-pn) where pn is the probability of a unit so in this case p(Up)=p[1 -((1-p)*(1-p)] p(Up)=2/3*(1-((1/3)(1/3))=18/27

then part b we do the same the top part is in series Top part=[p*p]=2/3*2/3=4/9 the bottom part=2/3 and we the apply this formula as they are now in parallel probability of a system being up in parallel=1 -((1-p1)*(1-p2)*..(1-pn) in this case it will be 1...