Stan makes a playlist for the next time he goes running. He has 10 3-minute songs and 15 2-minute songs on his playlist. His entire run takes 100 minutes. If Stan wants a playlist to cover his entire run, how many more minutes of songs will he need in his playlist?
His playlist currently has a playtime of 10 songs * 3 minutes = <<10*3=30>>30 minutes from 3-minute songs.
It also has a playtime of 15 songs * 2 minutes = <<15*2=30>>30 minutes from 2-minute songs.
So far, his playlist lasts for 30 + 30 = <<30+30=60>>60 minutes.
He therefore still needs 100 minutes for his run – 60 minutes current playtime = <<100-60=40>>40 minutes.
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