I assume that the question is meant to give insight into how they solve a problem that on the face of it looks straight forward? It isn't though. First assume

I assume that the question is meant to give insight into how they solve a problem that on the face of it looks straight forward? It isn't though. First assume that all datetime stamps are in UTC, otherwise we have opened a can of worms that still trip experienced developers. Now draw a "timeline" and start enumerating the different cases. Then you can make a reasonable solution. But I would only expect this from experienced developers or people with a higher degree.