This does not quite compute, these cannot be ALL the possible combinations, surely even you can see that! How do you come up with the dimensions of the square and the possible combinations which are so obviously wrong. Can anyone else see this? Also what about if the other woman arrive 10 minutes and one second later in each of the possible ten minutes this would represent at least 5.4 possibilies in addition to any other combinations. So I don't quite agree with your answer. Please explain in more depth. Either that or I must be really thick!