Online Access Free CRE Exam Questions

Develop the fault tree analysis for a candy dispensing machine. There are two contributing subsystems, both of them must fail for the system to fail. The electronic release has Pf = 0.04 and the coil spring release has Pf = 0.06. What is the system's probability of failure?

Response:

• A.0.0100
• B.0.0098
• C.0.0024
• D.0.0124

Top probability of the top event is represented by which of the following expressions?

Response:

• A.Pr(B1) + Pr(B2)
• B.Pr(B1) + Pr(B2) - Pr(B1) Pr(B2)
• C.Pr(B1) Pr(B2) - [Pr(B1) + Pr(B2)]
• D.Pr(B1) Pr(B2)

If a test shows three failures in 50 hours of operation, how many failures will it show in 1000 hours of operation if the failure rate is constant?
Response:

• A.150
• B.333
• C.20
• D.60

When performing trade-offs in evaluating parts for reliability, which of the following is LEAST important?
Response:

• A.Initial parts costs.
• B.Process and materials compatibility.
• C.Search of data part history to established reliability potential.
• D.Technical comparison of new part with standard part type.

The mean of the normal logarithms of the repair times is 4.3 hours with a standard deviation of 0.7 hours. What is the maintainability for an allowed repair time of 120 hours?
Response:

• A.0.187
• B.0.757
• C.0.976
• D.0.243