I figured out this percent composition problem and I got REALLY close answers, so I wanted to check in with someone to confirm if this is right.

Which is the better ore for mining Aluminum: Either Al2(CO3)3 or AlPO4? For me the first one was the better percentage (22.85%) but this was only off by a few tenths of a decimal point from AlPO4, at least the way I did it. Am I correct?