Mindbreakers... Puzzles!!!

Have you ever played Professor Layton video games? Maybe it look like a little childish, but it isn't. It is a great training for your mind and is so addictive. When you start a puzzle and you can't solve it, you will be on your sit for a big time trying to find an answer. I have decided to put some puzzles on this blog so we can train our mind and, of course, our English.

Let's start with the first one:

There is a professional golf player and he is really good at it (not like other professionals). He is an expert on "putts" of 3, 5, 7 and 11 metres. He is at the eighteenth hole, 20 metres before it.

Using his expert "putts", what is the low number of hits the golfer have to do for putting the ball inside the hole?

Come on, think a little and DO NOT LOOK FOR THE ANSWER!!!
I'll post the solution with the next post on Friday or Saturday.

I'm waiting your answer on the comments.