help a noob

first, which traits does lucky influenciates on ?
second, if my survivor has lucky, does it influenciate the weapon traits ?
third, the weapon lucky trait influenciate the survivor traits ?
the last one, if i have lucky trait on both, survivor and weapon, and if the second and\or third questions works, the % of the luckies are added ? an example, 10% on trait, 15% on weapon, then would i have 25% lucky ?