Originally posted by Alcra
Are the bugs evenly spaced to begin with. If so, are they spaced 10 to the centimetre? Are they spaced with equal chance of facing left/right?
The bugs are not necessarily evenly spaced. They can be initially distributed along the ruler in any arbitrary fashion.
The probability that any one bug faces right (or left) initially is also unrestricted.
The problem is to find the maximum amount of time that it could possibly take for all of the bugs to fall off the ruler, so you may want to think about what starting configuration is limiting in this sense.
my hint would be that it is very easy to overthink this problem...