Translation:He is looking at the colors of the house.
I also thought it said kolorajn. I event put it as part of my answer and Duolingo said it was correct. Not understanding, I came to the comments hoping to find out why colors was kolorajn vice kolorojn. Does not appear that it should be correct. One slipped by the goalie, I guess.
I just listened. The audio is correct.
Just like others have said, it does sound like "kolorajn". Grammatically it has to be a noun so I thankfully put -ojn