Answer: 408/x
Explanation:
Total number of people = 816
after 1 song = 816/2 people remained
after 2 songs = 816/4 people remained
after 3 songs = 816/8 people remained
after x songs = 816/x*2 people remained
People that remained = 816/2x
where x is the number of songs
Simplified = 408/x