How do you calculate the combined reliability of a bearing system with multiple bearings?

For a system with n bearings, combined L10 life is calculated using: (1/L10_system)^e = sum(1/L10_i)^e, where e = 10/9 (Weibull slope for bearings). For different reliability R, use Lna = a1 x L10, where a1 is reliability factor (0.62 for 95%, 0.33 for 97%). For two bearings with L10 = 5000 and 8000 hours, system L10 = [(1/5000)^1.11 + (1/8000)^1.11]^(-0.9) = 3,400 hours. Consider load distribution, speed variations, and adjusted rating life a_ISO for lubrication and contamination effects.