Scarlett purchased five new mp3s. She has room to add only three more onto her mp3 player. How many possible combinations of songs can be added to her mp3 player?
A. 10
B. 20
C. 30
D. 60
This will be P(5,3), that is the number of ways to choose 3 songs from 5, in some order
P(5,3) = 5!/(5-3)! = 60
see Probability for more info
EDIT: I think order counts here, so I changed C(5,3) to P(5,3)