Thirty-three ladybugs are sitting on a one meter stick. Suddenly all ladybugs start crawling either to the left or to the right with a constant speed of one meter per minute. When two ladybugs meet, they reverse directions immediately. If one arrives at the end of the stick, it falls off. Considering all possible initial configurations, what is the longest time it can take until all ladybugs have fallen off?

(In reply to Achieving the maximum by Steve Herman)

What you say is true, when the length of the lady bugs can be neglected. For finite-length insects, however, the maximum can only be reached when they do not bump into each other. This is what I meant in the solution.

Posted by JLo on 2020-01-12 08:24:37