"He has a big brown car."
Translation:عِنْدهُ سَيّارة بُنِّيّة كَبيرة.
My impression (and it's worked so far) is that, since Arabic puts adjectives AFTER the noun, unlike English, then you say the adjective that gives the new information at the very end. What I mean, in this case, is that the given is that he has a brown car, and the new information is that it's big. Do you agree? He has a brown-car, and it's big. So in Arabic, "brown sticks with the noun, and "big" goes second.
I had asked this exact question earlier in the course. https://forum.duolingo.com/comment/32923991?comment_id=33069922 I haven't found a good answer yet. There's also some discussion here: https://forum.duolingo.com/comment/32854689