A system is composed of three components A, B, and C. All three must function for the system to function. There are currently no backups in place. The system has a reliability of 0.966. If a backup is installed for component A, the new system reliability will be:
A) unchanged.
B) less than 0.966.
C) greater than it would be if a backup were also installed for component B.
D) greater than 0.966
E) none of these

Question

Quizplus · Accepted Answer

Since all three components must function for the system to function, the current system reliability of 0.966 is the probability that all three components are working simultaneously. If a backup is installed for component A, there are now two ways for the system to function: either A and B and C are working or Abackup and B and C are working. This increases the overall probability of the system functioning, meaning that the new system reliability will be greater than 0.966. Therefore, the correct answer is D.

A System Is Composed of Three Components A, B, and C