Answer :

Since the band has to be arranged in a rectangle arrangement, the way in which the players are going to be organized are going to be factors of 50. 
1st way: 1 by 50
2nd way: 2 by 25
3rd way: 5 by 10

Hope this helped!!
1*50
2*25
5*50
You can basically do any number that can go in 50