- 11

- 0

## Main Question or Discussion Point

**[SOLVED] probability of failure**

The performance of the valves in Q5 has been assessed in more detail under conditions

closer to those experienced in-service and the distribution functions of the random time

to failure have been quantified. The useful life period, prior to wear-out, occurs from

installtion to 5years. During this period, all of the distribution functions are modelled

using an exponential distribution function of the form:

FT (t) = 1 − exp[−_λit] where i=1,2,3,4,5

If _λ1 = λ_2 = _λ3 = 0.05; λ_4 = 0.267; λ_5 = 0.189 (all in years−1), calculate the probability

of a loss of flow from the manifold sometime in the period (0,3)years.

ANSWER[P[F]=0.08643]

ATTEMPT

Have tried to substitute .05 for lambada and 3 for t in the given equation but my answer is still very different from the given answer of 0.08643