Will you pass a ua if you drank 1 beer 4 hours earlier?

Yes. Because, for every one drink you have, it takes your liver one hour to get rid of one drink. So, if you were to have 6 drinks, you would have to wait 6 hours until all of the alcohol is out of your system. So, for example, lets say you had 6 drinks. At 9:30 pm you order your first drink and finish it by 9:35. At 10:35, that drink you finished an hour ago, is out of your system. Your liver can only get rid of one drink every one hour.