Unit rates are based on a single unit of something. Like price per 1 gallon of gas; price for 1 pound of bananas; miles driven per 1 gallon of gas, etc. What we are looking for in minutes per song.
Use a proportion to solve this with minutes on top and number of songs on the bottom. We know that 49 minutes = 8 songs, and we want to know how many minutes (x) per 1 song: