A complex electronic system is built with a certain number of backup components in its subsystems. One subsystem has four identical components, each with a probability of 0.25 of failing in less than 1,000 hours. The sub system will operate if any two of the four components are operating. Assume that the components operate independently. (Round your answers to four decimal places.) (a) Find the probability that exactly two of the four components last longer than 1,000 hours