Funny Joke

There was a old man and a teenager at a bar , the old man said to the teenager .I bet you I can drink 2 beers before you can drink 2 shooters and any shooters you pick. And the old man bet $200 for the teenager and the teenager puts $200 also,but the old man said but there is a catch "We are not allowed to touch each other glasses " and the teenager agree .The old man ask can he drink his first beer and then they can begin,the boy know his going to win because is two shots glasses and say go ahead , as the old man finish his first beer he put the glass upside down on the one shooter glass and said let us Begin.