Thanks Blake, that is a great idea to highlight common situations.
It made me dust off my rules book, which is good occasionally. I don't think the questions are as straight forward as they seem.
The circles appear to be drawn at 2 hull lengths radius, rather than the 3 hull lengths radius as per the RRS definition of the ‘zone’. Can we presume the inside boat established his overlap in time, as the first of them reaches the (3 hull length) 'zone'?