How long does it take to go from finding an agent to getting published?

How long does it take to go from finding an agent to getting published?

Derek Johns (Managing Director - AP Watt Literary Agency) gives expert video advice on: How long does it take to go from finding an agent to getting published?; What happens when a book is accepted for publication?; What should I do if a publisher asks me to make revisions before they accept my submission? and more...