Why am I only allowed to answer 20 questions per day on Answers?

at level 1 your level that's the maximum allowed. It's really no big deal, it's an effort to control spam and nonsense posts and encourage new members to familiarize themselves with the site. There are seven levels, as you move up in level you earn more participation rights, at level 2, 250 points which you can easily reach in a week then it goes up, you can ask 10 questions and most important answer 80 so you can really start accumulating points, it's important is to choose best answer to your questions, after an hour and at least one answer return to your question, click the blue best answer button of the one you choose,you get 3 points back of the 5 it cost you to ask and the member who helped you the most is a happy camper, they earned a bonus 10 points check the link.

http://answers.yahoo.com/info/scoring_system;_ylt=...

Because you are still a Level 1 user. Lower levels have lower limits, to limit input from spammers and trolls, and to let new users learn the site slowly. Answer more than you ask, accumulate at least 250 total points, and you get to Level 2 with higher daily limits. This is all explained on the "Points & Levels" link on the ABOUT link at the bottom left of the page.

You are level 1,which is entry level,once you reach 250 points you will be level 2 and can answer and ask more questions.You get 2 points for answering questions,and 10 points if you get best answer.