A product has three components, A, B, and C, with reliabilities of 0.95, 0.98, and 0.995. Engineers intend to put a redundant component A that has reliability 0.70. With this change, system reliability will
A) fall by 20%
B) fall by 10% or less
C) rise
D) cannot determine from the information provided
E) none of the above

Question

Quizplus · Accepted Answer

To find the new reliability, we need to use the formula for parallel components:
R_total = 1 - (1 - R_A)(1 - R_B)(1 - R_C)
where R_total is the reliability of the system with the redundant component A and R_A, R_B, and R_C are the reliabilities of components A (redundant), B, and C, respectively.

Substituting the given values, we get:
R_total = 1 - (1 - 0.70)(1 - 0.98)(1 - 0.995)
R_total = 0.99916

Therefore, the system reliability will rise to 0.99916, which is higher than the original reliability of 0.95. Therefore, the answer is C) rise.

A Product Has Three Components, A, B, and C, with Reliabilities