You see, a boat filled with people riddle is a fascinating and trick riddle. The question is not related to maths, and no calculation is required to solve the puzzle.
Riddle: “You see a boat filled all with people and You look again towards it but this time you don’t see a single person on the boat this time Why?”
Answer: The answer to this riddle is all the people on the boat are Married. That’s why you don’t see a single person when you look again. This riddle answer is not about the numbers, and the single denotes to the unmarried persons on the boat.