15 songs cost $9.75.
To find the cost of each song, divide the two numbers.
9.75/15 = 0.65
Each song costs $0.65.
For 18 songs,
18 × 0.65 = 11.7
18 songs cost $11.70.
To find the number of songs you can buy with $20 (x=number of songs),
0.65x = 20
x = 30.8
Since you're buying songs, you can only have a whole number. This means you must round down to 30.
You can buy 30 songs with $20.00.
