11.15.

(a) Suppose that a components are hooked up in a series arrangement. Then k such series connections are hooked up in parallel to form an entire system. (See Figure 11.10.) If each component has the same reliability, say R, for a certain period of operation, find an expression for the reliability of the entire system (for that same period of opera- tion).

(b) Suppose that each of the above components obeys an exponential failure law with failure rate 0.05. Suppose furthermore that the time of operation is 10 hours and that n = 5. Determine the value of k in order that the reliability of the entire system equals 0.99.