Problem 20
Suppose that you have n dollars to spend on music. Songs either cost 1 dollar or 2 dollars, depending on their release date. How many ways are there to spend n dollars on music? Express your answer as a simple function of n.
Example: For n = 3
You can buy:
3 one dollar songs or
1 two dollar song and 1 one dollar song
= 2 different ways to spend three dollars
