6) Assume given an electrical network with 3 vertices's and four segments between those vertices's: (see black board) the segments a and b go in parallel from ~ to y, whilst d goes from y to 2. Finally c goes also from y to z. Each of the segments works independently form the others. Let A be the event that segment a works, let B be the event that segment b works, ... Let pa be the probability that a works, hence pa = P(A). Let p; be equal to P(B),... We assume that pa, Pb, Pe, pa are all given to us. Let E be the event that electricity can flow from a to z. Calculate P(E) in terms of Pa, Pb, Pc and Pa