percentage

-EquinoX-

1. The problem statement, all variables and given/known data

If I have two system A with failure rate of X and two system B with failure rate of Y then what would be the combined failure rate of system A and B?

2. Relevant equations



3. The attempt at a solution

I know how to find the combined failure rate of A and the combined failure rate of B.
So I just add them and divide by 2?