Yes, there must be some kind of trick here
There are 10 people in total. So each can only shake hands with max 8 people (exluding therselves and partner). It quotes that everyone shook hands so minimum number of shakes by a person is 1. So the range of shakes is 1 thru 8. but he asked 9 people, there aren't 9 integers in the range 1-8. Maybe a maid or gay couples as already posited.
