If you know the correct answer to a question, you should post it — whether or not you are the original poster of the question. This is true whether you know the answer from the start (i.e., at the time you posted the question) or learned it later.
It's good to ask and answer questions you know the answer to, because once you put your knowledge into the system, other people can draw from it.
If you have any questions, please just reach out to us. We're always happy to help!