The Stone Roses' Second Coming had 99 tracks but most of them were silent and lasted for a second or two.
Either way, if they're audio tracks then you can fit 80 minutes worth onto an 80 minute disc - it'll just depend on how long the songs are (The End by The Doors is considerably longer than the average Green Day song!).
If they're saved as mp3, again it depends how long the song is and what quality the files are encoded at : 128Kbps is pretty standard and anything higher (or lower) than this will make the file larger (or smaller).
In this case you're measuring against the 700mb capacity rather than the 80 minutes.