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# MTBF Question

## MTBF Question

(OP)
Hi.
I am new to this and have to work out a systems reliability that has 4 components all in parallel.  The MTBF's I have calculated for each system using the failure rates and MTBF's. These are A = 1433 hours, B = 1443 hours, C =1342 hours and D = 1232 hours.  To calculate the systems overall MTBF I have converted these to failure rates and multiplied them ie A x B x C x D. giving me 2.92499E-13.  I have then done
1 / 2.92499E-13 giving me a MTBF of the system of 4.25455E+12 hours.  Is this correct as it seems very high.

Many thanks

### RE: MTBF Question

(OP)
Hi IRStuff.

Thanks for that, they are fully redundant but have different MTBF's as the each system is composed of different parts although do the same thing, should one go down.

Cheers

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