When you calculate the total possibilities, you don't assume the desired outcome. You're calculating the probability GIVEN that a song CAN'T repeat before all the songs have been played. But, that's a component of the situation you're looking for, not a rule.Dabney said:I don't agree...
the task is, that the ten songs are played in the right order, so no song can be played twice. Otherwise one song would be missing.
So you have ten possibilities for track 1, and as only one song is right the probability is 1/10. Then there are only 9 songs left, so the probability for track 2 is 1/9. Then there are only 8 songs left, so the probability is 1/8 and so on. :Smart: