A device consists of 100 independent modules of equalfunctionality. Zk is the event that the kth group works reliably.a) What is the probability that the device will work reliably at P(Zk) = 99%?
There are four independently operating machines in a hall, which donot fail within a certain period of time with the probabilities0.9, 0.95, 0.8 and 0.85, respectively. Calculate the probabilitythat in this period a) all four machines work b) no machine worksc) exactly one machine works d) exactly two machines work e)exactly three machines work f) at least one machine works
