High school mathematics "excuse me, five people stand in a row, what is the probability that A and B are not adjacent?"
First of all, the remaining three people are all lined up, 3× 2× 1 = 6, A and B have a gap row, and three people have four empty seats C? 0? 5? 6? 2 = (4× 3)/2 = 6, so there are 6× 6 = 36 cases where Party A and Party B are not adjacent, and there are 5× 4× 3× 2× 1 = 120 cases where five people stand in a row, so the probability that Party A and Party B are not adjacent is 36/120.