For this problem, my task is simple. I have to be able to "summarize what key concepts are being explained in the example. I have to summarize what the problem is explaining and the bottom-line concepts described in the problem."

Can you help me summarize what this problem is stating and be able to explain it in basic English? Thank you.

One branch of reliability theory, called topological reliability, is concerned with calculating the reliability of systems comprising several components connected in specic patterns. One common layout for components is the series system (Figure 5.9), in which the system operates correctly only if each of its subcompo nents works correctly. A familiar example of such a system is a circuit with two switches, both of which must be closed for the circuit to conduct electricity. It is commonly assumed that the components are independent when performing reli- ability calculations. a Figure 5.9 A two-component series system, which functions correctly only if both components function correctly Suppose that the switches A and B in a twocomponent series system are closed about 60% and 80% of the time, reSpectively. If we assume that the clos- ing of switch A occurs independently of switch B, the probability that the entire circuit is closed is P(circuit closed) = P(A closed and B closed) = P(A closed) P(B closed) = (.60)(.80) = .48 That is, the circuit will be closed about 48% of the time