Marco has room for 15 more minutes of songs on his mp3 player. he has 3 songs to upload with the following lengths: 5.15 minutes,3.8 minutes, and 4.4 minutes. After uploading all three songs, about how many minutes will he have left?

He has room for 15 more minutes.
He uploaded 3 songs with the times 5.15, 3.8, and 4.4.
5.15 + 3.8 + 4.4 = 13.35

He now added 13.35 more minutes onto his mp3 player.
To find the room in minutes he has left, subtract that number from 15.
15 - 13.35 = 1.65

He has 1.65 minutes left.