Joseph Smith's experience following James 1:5 which says God will answer your prayers, is instructional for all of us.  My friend Lloyd, who passed away in 2012, had a similar experience with prayer.  In a situation where his personal strength and intelligence were not enough, Lloyd prayed and received an answer in a way anyone can receive an answer to a prayer.  You don't need to be without sin to have your prayers answered.  God knows people with sins and other problems are often the ones who need their prayers answered the most.