I'd like to know how many questions a person is allowed to post per day. Please include a link to the pertinent answer. I searched the site in vain for the answer.
You can post as many questions per day as you want, until the site limits you. However, whether those questions will be good is another question entirely. Generally, if you post more than one question per day, it's almost certain that there wasn't much effort put into the questions. And in that case, they will likely not be well-received.
Please see this answer for rate limits. As Deusovi says, if you're bumping into the site limits then you should ask yourself if your questions are really as polished as they should be.