It has been mentioned in the question clearly that if there are 2 womens with one men then they would run away he has no where mentioned that if there are more than 2 i., 3 they will run away together. I have given the explanation considering that.anyways @@shadowspirit has solved it considering...
@magpies If your answer was in continuation to what einsteinian77 has written then it would not work in the very first permutation where he mentions that: "The king and queen cross over first. Then the queen goes back to pick up the knights' wife and drops herself, the queen, off with her king."...
@@einsteinian77: "Then the knights' wife goes and picks up the servents' wife. The knights wife is dropped off w/ the king, queen, and the knight."
When the knights wife returns to pickup servants wife again the equation is one men and 2 wifes so the answer is wrong