In how many ways can a photographer at a wedding arrange six people in a row, including the bride and groom, if the bride is positioned somewhere to the left of the groom?
Assuming the bride is at the furthest to the left spot:
Why is the first line 5!
Assuming she's at the 2nd spot:
Why is it $4*4!$
If someone could explain that would be appreciated
Best Answer
The easiest way to solve this is to observe that there are $6!=720$ permutations of the $6$ people. In half of these, the bride is to the right of the groom, and in half of them, the bride is to the left of the groom.
So the answer is $\dfrac{6!}{2}=360.$