I am working the following probability problem which I came across online:
A computer network has 5 paths to its destination. Each path has a 20% chance of working and each path is independent. Am I guaranteed that at least one path will work?
I first answered it like:
P(1st path working OR 2nd path working OR 3rd path working OR 4th path working OR 5th path working) = 0.2 + 0.2 + 0.2 + 0.2 + 0.2 = 1
but apparently that is not correct. Can someone explain why?